Afforested sites in a temperate grassland region: influence on soil properties and methane uptake     

M. E. Priano  V. S. Fusé  S. Mestelan  A. M. Berkovic  S. A. Guzmán  R. Gratton  M. P. Juliarena 《Agroforestry Systems》2018,92(2):311-320

Methane (CH₄) flux at the soil-atmosphere interface (SAI) results from the balance between CH₄ production (methanogenesis) and CH₄ consumption (methanotrophy). The latter predominates in well-aerated mineral soils; is affected by a combination of abiotic and biotic factors, especially soil diffusivity, which depends on soil properties, and methanotroph activity. This work reports results of CH₄ fluxes from afforested sites located in a temperate region of formerly native grassland in Buenos Aires Province (Argentina, Southern Hemisphere), taking a naturalized pasture as a reference. Methane concentration [CH₄] and soil parameters along the soil profile were also measured to understand intersite differences in CH₄ fluxes at the SAI, that could be related to vegetation cover and its influence on soil properties and therefore, on CH₄ soil diffusivity. At all sites soils were CH₄ sinks in the range of ?3.55 to ?14.39 ng CH₄ m^?2 s^?1; the naturalized pasture presented the weakest one. Intersite differences in CH₄ fluxes may result from differences observed in [CH₄] profiles and CH₄ diffusion coefficients. [CH₄] variation could be explained mainly by differences in silt and clay content and bulk density that affect CH₄ soil diffusivity. These could be the result of afforestation that seems to improve the physical and biological soil attributes linked to CH₄ consumption as it meliorates its diffusivity.  相似文献   

Taking the pulse of forest plantations success in peri-urban environments through continuous inventory     

Barbara Ferrari  Piermaria Corona  Leone Davide Mancini  Riccardo Salvati  Anna Barbati 《New Forests》2017,48(4):527-545

Urban expansion increases the need for, and pressure on, green areas. Reforestation projects in the rural–urban fringe represent an opportunity for enhancing the environmental quality of peri-urban spaces and a means to contribute to cities carbon neutrality policies. Yet, relatively little information exists regarding the long term (10–25 years) survival and growth rate in urban and peri-urban plantations. This paper reports and discusses the results achieved by a reforestation in the peri-urban space of Rome (Italy), 25 years after its establishment. The plantation has been periodically surveyed between 6 and 24 years of age by means of continuous inventories, with the aim of monitoring growth dynamics. Permanent sample plots have been investigated and stratified by tree species composition (broadleaves vs. conifers, single vs. multispecies) for data analysis. On the whole, plantations show suitable results in terms of rate of growth, carbon storage and uptake, especially in coniferous and mixed stands. The average stand volume of the forest plantation, currently ranges from one-and-a third to one-and-a-half times the average values estimated for natural high forest stands of the same age and species groups at country level. The species groups exhibit differential growth patterns over the observed period, that are mainly due to differences in the ecological traits of the planted trees. Ten years after the establishment, the average annual value of carbon uptake in conifer and mixed species group exceeds 10 Mg CO₂ equivalent ha^?1 year^?1, a figure corresponding to 4 times the value of deciduous broadleaves (oaks and other species) and 1.5 times the value of evergreen oaks. Twenty years after the establishment, the average annual carbon uptake peaks to 25 Mg CO₂ equivalent ha^?1 year^?1 in the mixed species group, exceeds 15 Mg CO₂ equivalent ha^?1 year^?1 in the conifers, and ranks between 6 and 12.5 Mg CO₂ equivalent ha^?1 year^?1 in the groups dominated by broadleaved species. Overall with a surface area just under 300 ha, the carbon uptake level of the Castel di Guido reforestation allows to offset the 0.04% of CO₂ emissions of the city of Rome. Although the spatial coexistence of even-aged plantation blocks characterized by a range of ecological traits, is expected to ensure a more continuous carbon sequestration, being less susceptible to damage of any kind, the current lack of silvicultural management may also lead to degradation processes, by triggering e.g. fuel accumulation and, by consequence, forest fires. In this line, recommendations are provided in order to improve the ecological and functional efficiency of the investigated reforestation. The field experiment demonstrates, ultimately, the capability of the continuous forest inventory to take the pulse over several decades of tree species performance and carbon uptake levels in urban and peri-urban reforestations.  相似文献   

Floristic diversity,carbon storage and ecological services of eucalyptus agrosystems in Cameroon     

V. Noiha Noumi  L. Zapfack  M. R. Hamadou  V. Awe Djongmo  N. Witanou  B. Nyeck  J. D. Ngossomo  R. B. Tabue Mbobda  P. M. Mapongmetsem 《Agroforestry Systems》2018,92(2):239-250

Although agrosystems are recognized for their socio-economic value, few works have been conducted to assign its sequestration potential and ecological services. Accordingly, this study aimed to evaluate the ecological services of the eucalyptus stands in order to permit to small producers the access in carbon credit market. Three stands were selected according to age. Data were compared to that of a savannah (control). In total, 12,817 individuals belonging to 30 families, 53 genera and 70 species were identified in the plantations against 7107 individuals belonging to 24 families, 36 genera and 42 species in the savannah. Gmelina, Annona, Hymenocardia, Allophyllus, Daniellia, Terminalia and Piliostigma were the most represented genera. There was no significant difference between Savannah and plantations in terms of diversity (p > 0.05). The largest stock of carbon was found in oldest stands (108.51 ± 26.46 t C/ha) against 13.62 ± 3.03 t C/ha in Savannah. Eucalyptus saligna stored 39.66 t C/ha (4 t C ha^?1year^?1) in young stands; 57.28 t C/ha (6 t C ha^?1year^?1) in medium stands and 85.46 t C/ha (9 t C ha^?1year^?1) in old stands. The sequestration potential was higher in eucalyptus stands (398.25 t CO_2eq/ha) than savannah (50.05 t CO_2eq/ha). In total 956.82 t CO_2eq/ha were sequestered for an economic value of $9568.45/ha against 50.05 t CO_2eq/ha corresponding to $500.56/ha in Savannah. Eucalyptus stands are carbon sinks and could be an opportunity for financial benefits in the event of payment for environmental services in the context of the CDM process.  相似文献   

Earthworm population and microbial activity temporal dynamics in a Caspian Hyrcanian mixed forest     

Mohammad Bayranvand  Yahya Kooch  Ana Rey 《European Journal of Forest Research》2017,136(3):447-456

Few studies have analyzed how tree species within a mixed natural forest affect the dynamics of soil chemical properties and soil biological activity. This study examines seasonal changes in earthworm populations and microbial respiration under several forest species (Carpinus betulus, Ulmus minor, Pterocarya fraxinifolia, Alnus glutinosa, Populus caspica and Quercus castaneifolia) in a temperate mixed forest situated in northern Iran. Soil samplings were taken under six individual tree species (n = 5) in April, June, August and October (a total of 30 trees each month) to examine seasonal variability in soil chemical properties and soil biological activity. Earthworm density/biomass varied seasonally but not significantly between tree species. Maximum values were found in spring (10.04 m^?2/16.06 mg m^?2) and autumn (9.7 m^?2/16.98 mg m^?2) and minimum in the summer (0.43 m^?2/1.26 mg m^?2). Soil microbial respiration did not differ between tree species and showed similar temporal trends in all soils under different tree species. In contrast to earthworm activity, maximum microbial activity was measured in summer (0.44 mg CO₂–C g soil^?1 day^?1) and minimum in winter (0.24 mg CO₂–C g soil^?1 day^?1). This study shows that although tree species affected soil chemical properties (pH, organic C, total N content of mineral soils), earthworm density/biomass and microbial respiration are not affected by tree species but are controlled by tree activity and climate with strong seasonal dynamics in this temperate forest.  相似文献   

Long-term response to area of competition control in <Emphasis Type="Italic">Eucalyptus globulus</Emphasis> plantations     

F. Vargas  R. Rubilar  C. A. Gonzalez-Benecke  M. Sanchez-Olate  Pablo Aracena 《New Forests》2018,49(3):383-398

Numerous studies have quantified the responses to vegetation management in Eucalyptus plantations but most publications have reported early responses in tree growth and a gap in knowledge exist about the magnitude and duration of growth responses throughout the whole rotation. We evaluated the long-term response (9 years-old) of E. globulus across a gradient of sites to different intensity levels of free area of competing vegetation around individual tree seedlings. Competing vegetation intensity levels considered free areas ranging between 0 (control) to 2.54 m² plus a treatment with total weed control. Competing vegetation biomass production during the first growing season was 2.9, 6.5, 2.2 and 12.9 Mg ha^?1, for sites ranging from low to high annual rainfall. Across sites, maximum response in stand volume ranged between 58 and 262 m³ ha^?1 at age 9 years and was proportional to the amount of competing biomass controlled during the first growing season. Total competing vegetation control showed the largest response in stand volume at sites with 2.9 and 12.9 Mg ha^?1 of competing vegetation. However, the 2.54 m² vegetation control treatment showed the maximum response for sites with 2.2 and 6.5 Mg ha^?1 of competing vegetation. The duration of response for vegetation control treatments ranged between 5 and 9 years. However, at the site with the largest accumulation of competing vegetation biomass the response to vegetation control showed a sustained and divergent response. Our results suggest that vegetation control improved site resources acquisition increasing long-term stand productivity by reducing environmental limitations to tree growth differentially at each site.  相似文献   

Tree row spacing affected agronomic and economic performance of Eucalyptus-based agroforestry in Andhra Pradesh, Southern India   总被引：1，自引：1，他引：0  

J. V. N. S. Prasad  G. R. Korwar  K. V. Rao  U. K. Mandal  C. A. R. Rao  G. R. Rao  Y. S. Ramakrishna  B. Venkateswarlu  S. N. Rao  H. D. Kulkarni  M. R. Rao 《Agroforestry Systems》2010,78(3):253-267

The 3 × 2 m spacing currently used for eucalyptus plantations in the state of Andhra Pradesh, southern India does not permit intercropping from the second year. This discourages small landholders who need regular income from taking up eucalyptus plantations and benefiting from the expanding market for pulpwood. Therefore, on-farm experiments were conducted near Bhadrachalam, Khammam district (Andhra Pradesh) for over 4 years from August 2001 to November 2005 to examine whether wide-row planting and grouping of certain tree rows will facilitate extended intercropping without sacrificing wood yield. Eucalyptus planted in five-spatial arrangements in agroforestry [3 × 2 m (farmers’ practice), 6 × 1 m, 7 × 1.5 m paired rows (7 × 1.5 PR), 11 × 1 m paired rows (11 × 1 PR) and 10 × 1.5 m triple rows (10 × 1.5 TR)] was compared with sole tree stands at a constant density of 1,666 trees ha^?1. Cowpea (Vigna unguiculata) was intercropped during the post-rainy seasons from 2001 to 2004, and fodder grasses (Panicum maximum and Brachiaria ruziziensis) were intercropped during both the seasons of 2005. At 51 months after planting, different spatial arrangements did not significantly affect height and diameter at breast height (dbh). Total dry biomass of eucalyptus in different spatial arrangements ranged between 59.5 and 52.9 Mg ha^?1, the highest being with 6 × 1 m and the lowest with 10 × 1.5 TR, but treatment differences were not significant. The widely spaced paired row (11 × 1 PR) and triple row (10 × 1.5 TR) arrangements produced 62–73% of sole cowpea yield in 2003, 59–66% of sole cowpea yield in 2004, and 79–94% of sole fodder in 2005. In contrast, the 3 × 2 m spacing allowed only 17–45% of sole crop yields in these years. The better performance of intercrops in widely spaced eucalyptus was likely because of limited competition from trees for light and water. Intercropping of eucalyptus in these wider rows gave 14% greater net returns compared with intercropping in eucalyptus spaced at 3 × 2 m, 19% greater returns compared with that from sole tree woodlot and 263% greater returns compared with that from sole crops. Therefore, in regions where annual rainfall is around 1,000 mm and soils are fairly good, eucalyptus at a density of 1,666 plants per ha can be planted in uniformly spaced wide-rows (6 m) or paired rows at an inter-pair spacing of 7–11 m for improving intercrop performance without sacrificing wood production.  相似文献   

Dynamics of soil-derived greenhouse gas emissions from shelterbelts under elevated soil moisture conditions in a semi-arid prairie environment     

Chukwudi C. Amadi  Richard E. Farrell  Ken C. J. Van Rees 《Agroforestry Systems》2018,92(2):321-334

Soil moisture is known to be a major control of greenhouse gas (GHG) emissions from agricultural soils. However, there is little data regarding GHG exchange from the organic matter-rich soils characteristic of shelterbelts—especially under elevated soil moisture conditions. In the present study, we quantified CO₂, CH₄ and N₂O fluxes from shelterbelts under elevated soil moisture (irrigated) and semi-arid (rainfed) conditions. Studies were carried out at the Canada-Saskatchewan Irrigation Diversification Centre (CSIDC) near Outlook, Saskatchewan. Non-steady state vented chambers were used to monitor soil GHG fluxes from three shelterbelts in 2013 and 2014. The shelterbelts consisted of a single row of caragana with a north–south orientation and a single row of Scots pine with either a north–south or east–west orientation. Each shelterbelt was divided into two areas based on whether or not it received irrigation. During the 2-year study period, N₂O emissions from the irrigated shelterbelts (IR-SB) (0.93 kg N₂O-N ha^?1) were significantly greater than those from the rainfed shelterbelts (RF-SB) (0.49 kg N₂O-N ha^?1). Soil CH₄ oxidation was significantly lower in the IR-SB compared to the RF-SB (?0.85 and ?1.20 kg CH₄-C ha^?1, respectively). Irrigation activities stimulated CO₂ production/emission in 2014, but had no effect on CO₂ emissions during the much drier 2013 season. Correlation analyses indicate a strong dependence of CO₂ and CH₄ fluxes on soil moisture in both IR-SB and RF-SB sites. There was a significant relationship between N₂O emissions and soil moisture for the IR-SB sites in 2013; however, no such relationship was observed in either the IR-SB or RF-SB sites in 2014. Our study suggests that changes in precipitation patterns and soil moisture regime due to climate change could affect soil-atmosphere exchange of GHGs in shelterbelts; however, elevated soil moisture effect on GHG emissions will depend on the availability of N and C in the shelterbelts.  相似文献   

Carbon dioxide sequestration capability of an unmanaged old-growth broadleaf deciduous forest in a Strict Nature Reserve     

Mirko U. Granata  Loretta Gratani  Francesco Bracco 《Journal of Sustainable Forestry》2019,38(1):85-96

The seasonal trend of plant carbon dioxide (CO₂) sequestration is related to the photosynthetic activity, which in turn changes in response to environmental conditions. Great interest has turned to the CO₂ sequestration (CS) potential of temperate forests which play an important role in global carbon (C) cycle contributing to the lowering of atmospheric CO₂ concentration. In such context, the CS of an unmanaged old broad-leaf deciduous forest developing inside a Strict Nature Reserve, and its variations during the year were analyzed considering the monthly variations of leaf area index (LAI) and net photosynthetic rates (N_P). Overall, the total yearly CS of the forest was 141 Mg CO₂ ha^?1 year^?1 with the highest CS value monitored in June (405 Mg CO₂ month^?1) due to the highest LAI (5.0 ± 0.8 m² m^?2) and a high N_P in all the broadleaf species. The first CS decline was observed in August due to the more stressful climatic conditions that constrained N_P rates. Overall, the total CS of the forest reflects the good ecological health of the ecosystem due to its conservative management.  相似文献   

Response of soil respiration to a severe drought in Chinese <Emphasis Type="Italic">Eucalyptus</Emphasis> plantations     

Shaojun Wang  Hong Wang 《林业研究》2017,28(4):841-847

Extreme droughts can adversely affect the dynamics of soil respiration in tree plantations. We used a severe drought in southwestern China as a case study to estimate the effects of drought on temporal variations in soil respiration in a plantation of Eucalyptus globulus. We documented a clear seasonal pattern in soil respiration with the highest values (100.9 mg C–CO₂ m^?2 h^?1) recorded in June and the lowest values (28.7 mg C–CO₂ m^?2 h^?1) in January. The variation in soil respiration was closely associated with the dynamics of soil water driven by the drought. Soil respiration was nearly twice as great in the wet seasons as in the dry seasons. Soil water content accounted for 83–91% of variation in soil respiration, while a combined soil water and soil temperature model explained 90–99% of the variation in soil respiration. Soil water had pronounced effects on soil respiration at the moisture threshold of 6–10%. Soil water was strongly related to changes in soil parameters (i.e., bulk density, pH, soil organic carbon, and available nitrogen). These strongly influenced seasonal variation in soil respiration. We found that soil respiration was strongly suppressed by severe drought. Drought resulted in a shortage of soil water which reduced formation of soil organic carbon, impacted soil acid–base properties and soil texture, and affected soil nutrient availability.  相似文献   

Soil and the foliage nutrient status following soil amendment applications in a Japanese cypress (Chamaecyparis obtusa Endlicher) plantation     

Jaeyeob Jeong  Chang Gyu Jo  Gyeong Won Baek  Jae-Hyun Park  Ho-Seop Ma  Byung Oh Yoo 《Journal of Sustainable Forestry》2017,36(3):289-303

The aim of this study was to evaluate the response of soil amendment applications on soil and the foliage nutrient status of a Japanese cypress (Chamaecyparis obtusa Endlicher) plantation established following clear-cutting in a pine-wilt-disease (PWD)-disturbed forest. We established four soil amendment treatments [(compound fertilizer (CF), compound fertilizer + biochar (CFB), compound fertilizer + sawdust (CFS) and a non-treated control treatment] in an 8-year-old Japanese cypress plantation. Soil organic carbon (C) and total nitrogen (N) were not significantly different (P > 0.05) between the soil amendment treatments and the control treatments, whereas extractable phosphorus (P), NH₄⁺, K⁺, and Mg²⁺ concentrations were significantly affected by the addition of biochar in CF. The mean soil CO₂ efflux rates during the study period were the highest in CFB (0.79 g CO₂ m^?2 h^?1), followed by CFS (0.71 g CO₂ m^?2 h^?1), CF (0.62 g CO₂ m^?2 h^?1), and the control (0.46 g CO₂ m^?2 h^?1) treatments. Foliar N and P concentrations were significantly higher in the CFB than in the control treatments. The results suggest that the addition of biochar in CF can enhance extractable soil nutrients and foliar N and P conditions of Japanese cypress established in a PWD-disturbed forest.  相似文献   

Assessment of leaf mass and leaf area of tree crowns in young Eucalyptus grandis and E. globulus plantations from measurements made on the stems     

S. J. Rance  D. S. Mendham  D. M. Cameron 《New Forests》2014,45(4):523-543

Leaf area is a key driver of growth models and leaf weight is important for studying carbon and nutrient cycling in forestry. Both can change over relatively short intervals in young plantations in response to silvicultural treatments and climatic conditions. Relationships to estimate leaf dry weight and leaf area of young Eucalyptus grandis W. Hill ex Maiden and Eucalyptus globulus (Labill.) were developed from harvested trees ranging from 0.28 to 15.85 m and 0.12 to 34.4 m in height respectively. Trees were harvested from existing experiments in south-eastern Queensland and south-west Western Australia in order to assess the effects of spacing and application of nitrogen and phosphorus fertilizer on early plantation growth. A range of tree measurements were taken to determine the most efficient way to monitor the performance of young plantation eucalyptus. Leaf weight (W_leaf, kg) and leaf area (m²) were related to stem cross sectional area at the height of the base of the green crown (SA_CB), but the slope and intercept of the relationship differed for trees with predominantly juvenile foliage and those with predominantly intermediate or adult foliage. Specific leaf area (m² kg^?2) changed as the trees aged and leaf area was more closely related to the size of the support structure, represented by the stem volume within the green crown, approximated by the volume of a cone above the base of the green crown (V_C,gc). Significantly, the relationships also applied to individual branches, that is, leaf weight was related to sectional area near the base of the branch (SA_b) and leaf area to the volume of the main (first order) branch (V_C,br). Most of the published work has been directed at trees of commercial size or to small trees in pot experiments, much less to small trees in the establishment phase of growth of interest to experimenters and managers looking at early intervention. This study provides a mechanism to directly assess canopies of intermediate size trees which are of interest for assessing treatment effects or early intervention for managers.  相似文献   

Woody biomass on farms and in the landscapes of Rwanda     

J. D. Ndayambaje  T. Mugiraneza  G. M. J. Mohren 《Agroforestry Systems》2014,88(1):101-124

Scattered trees and woodlots are a prominent feature of agricultural landscapes of Rwanda. However, little is known about their characteristics and their contribution to farmers’ wood needs. Here, we present the results of a survey of (a) the abundance, composition, and size of trees and woodlots in the low, medium and high altitude regions of Rwanda, (b) total woody biomass and biomass for fuelwood at farm and landscape levels, and (c) opportunities for their sustainable use. Scattered trees occurred in all landscapes at minimum densities ranging from 20 to 167 trees ha^?1. Of the 56 tree genera recorded, a handful of tree species dominated, with the ten most common species accounting for over 70 % of all trees recorded. Most of them provided fuelwood, fruit and timber to farm owners. Woodlots occurred on about 40 % of the survey farms and consisted for 90 % of eucalyptus coppice. Woody biomass dry weight of scattered trees on agricultural landscape was 0.7 t ha^?1 in low altitude region (LAR), 3 t ha^?1 in medium altitude region (MAR), and 1 t ha^?1 in high altitude region (HAR). Dry weight woody biomass in woodlots (<0.5 ha) was the highest in MAR (221 t ha^?1), followed by that in HAR (205 t ha^?1) and least in LAR (96 t ha^?1). About 80 % of total woody biomass in trees and woodlots on farmland was useable biomass for fuelwood, indicating that the production of fuelwood on agricultural land was important. Woody biomass on agricultural land was higher than that in forest plantations, and was potentially sufficient to reduce the gap between fuelwood supply and demand when the entire agricultural area was taken into account. In order to achieve this on agricultural land, while contributing to food security and environmental conservation as well, smallholder farmers must be provided with incentives to grow woodlots and to adopt agroforestry systems, thereby considering the trade-offs with agricultural production. Strategies to encourage smallholder farmers to increase the use of agroforestry have to account for the farmers’ ecological and socioeconomic conditions.  相似文献   

Long-term study of above- and below-ground biomass production in relation to nitrogen and carbon accumulation dynamics in a grey alder (Alnus incana (L.) Moench) plantation on former agricultural land     

Jürgen Aosaar  Mats Varik  Krista Lõhmus  Ivika Ostonen  Hardo Becker  Veiko Uri 《European Journal of Forest Research》2013,132(5-6):737-749

In the Northern and Baltic countries, grey alder is a prospective tree species for short-rotation forestry. Hence, knowledge about the functioning of such forest ecosystems is critical in order to manage them in a sustainable and environmentally sound way. The 17-year-long continuous time series study is conducted in a grey alder plantation growing on abandoned agricultural land. The results of above- and below-ground biomass and production of the 17-year-old stand are compared to the earlier published respective data from the same stand at the ages of 5 and 10 years. The objectives of the current study were to assess (1) above-ground biomass (AGB) and production; (2) below-ground biomass: coarse root biomass (CRB), fine root biomass (FRB) and fine root production (FRP); (3) carbon (C) and nitrogen (N) accumulation dynamics in grey alder stand growing on former arable land. The main results of the 17-year-old stand were as follows: AGB 120.8 t ha^?1; current annual increment of the stem mass 5.7 t ha year^?1; calculated CRB 22.3 t ha^?1; FRB 81 ± 10 g m^?2; nodule biomass 31 ± 19 g m^?2; fine root necromass 11 ± 2 g m^?2; FRP 53 g DM m^?2 year^?1; fine root turnover rate 0.54 year^?1; and fine root longevity 1.9 years. FRB was strongly correlated with the stand basal area and stem mass. Fine root efficiency was the highest at the age of 10 years; at the age of 17 years, it had slightly reduced. Grey alder stand significantly increased N and C_org content in topsoil. The role of fine roots for the sequestration of C is quite modest compared to leaf litter C flux.  相似文献   

Effect of multipurpose tree species on soil fertility and CO2 efflux under hilly ecosystems of Northeast India     

T. Ramesh  K. M. Manjaiah  J. M. S. Tomar  S. V. Ngachan 《Agroforestry Systems》2013,87(6):1377-1388

A 26 years old agroforestry plantation consisting of four multipurpose tree species (MPTs) (Michelia oblonga Wall, Parkia roxburghii G. Don, Alnus nepalensis D. Don, and Pinus kesiya Royle ex-Gordon) maintained at ICAR Research Complex, Umiam, Meghalaya, India were compared with a control plot (without tree plantation) for soil fertility status and CO₂ efflux. The presence of trees improved all the physico-chemical and microbial biomass parameters studied in this experiment. Relative to control, soils under MPTs showed significant increases of 17 % soil organic carbon, 26 % available nitrogen (AN), 28 % phosphorus (AP), 50 % potassium (AK), 65 % mean weight diameter (MWD) of aggregates, 21 % moisture and 34 % soil microbial biomass carbon (MBC) while reducing the mean bulk density (7 %). However, these parameters significantly differed among the tree species i.e., soils under A. nepalensis and M. oblonga had higher values of these attributes except bulk density, than under other species. Irrespective of treatments, the values of all these attributes were higher in surface soils while bulk density was highest in subsurface (60–75 cm). Cumulative CO₂ efflux under MPTs was significantly higher (15 %) and ranged from 1.71 g 100 g^?1 (M. oblonga) to 2.01 g 100 g^?1 (A. nepalensis) compared to control at 150 days of incubation. In all the treatments, increment in temperature increased the oxidation of soil organic matter, thereby increased the cumulative CO₂ efflux from soils. Of the tree species, with increment in temperature, A. nepalensis recorded more CO₂ efflux (2.50 g 100 g^?1) than other MPTs but the per cent increase was more in control plot. P. kesiya and A. nepalensis recorded highest activation energy (59.1 and 39 kJ mol^?1, respectively). Net organic carbon sequestered in soil was highest under A. nepalensis (25.7 g kg^?1) followed by M. oblonga (19.3 g kg^?1), whereas control showed the lowest values. Amount of net carbon stored in the soil had significant and positive correlation with MBC (r = 0.706**), MWD (r = 0.636*), and AN (r = 0.825**).  相似文献   

Optimal management of larch (<Emphasis Type="Italic">Larix olgensis</Emphasis> A. Henry) plantations in Northeast China when timber production and carbon stock are considered     

Wei Peng  Timo Pukkala  Xingji Jin  Fengri Li 《Annals of Forest Science》2018,75(2):63

  相似文献   

Young conifer stands form a deer browsing refuge for an oak admixture: silvicultural implications for forest regeneration under herbivore pressure     

Jakub Borkowski  Dorota Dobrowolska  Wojciech Dąbrowski  Rafał Banul  Dariusz Załuski 《European Journal of Forest Research》2017,136(5-6):787-800

There is little knowledge how ungulate pressure on forest regeneration may be mitigated by silvicultural methods. The knowledge is especially needed for artificially regenerated, deciduous tree species. We studied factors affecting browsing incidence by deer in the Pisz Forest District in Poland, an area where 10,000 ha of forest was damaged by a 2002 hurricane. In 2006, we established three experimental plots (in total, 22.6 ha), in which the main species was Scots pine (Pinus sylvestris) admixed with pedunculate oak (Quercus robur). The data on browsing were collected in 2008–2015. In general, oak browsing incidence was unrelated to oak planting density. On a plantation scale, it was significantly affected by the pine age. Although in each variant all the oaks were browsed for four consecutive years (2009–2012), in 2013 browsing incidence began to decrease. When the pines grew higher and formed a physical barrier, it was harder for deer—roe deer (Capreolus capreolus), red deer (Cervus elaphus) and moose (Alces alces)—to move through and locate the oaks. Moreover, within plantations, oak browsing incidence was higher in the patches with shorter pines. Browsing of individual saplings or small groups of saplings was also negatively affected by the height of neighbouring pine saplings. Oak density influenced deer selectivity depending on the tree height. In a low oak tree density, browsing incidence was unrelated to oak height, while in higher tree density, deer selected oaks of the height between 40 and 100 cm. We postulate that deciduous admixture in a coniferous (unattractive) stand can be planted with a few year delay. Older coniferous trees should impede locating of attractive tree species by deer and the browsing incidence.  相似文献   

Effect of tree spacing on growth and wood density of 38-year-old Cariniana legalis trees in Brazil     

《Southern Forests》2013,75(4):311-318

Average wood density of 38-year-old Cariniana legalis (Mart.) Kuntze, a Brazilian native forest species, was found to increase with faster growth and lower stocking, while decreasing from pith to bark. A complete randomised block design was planted with five blocks. Ten trees were harvested in each of three spacing treatments. We hypothesised that the stand stemwood production would not significantly differ depending on tree spacing. However, tree growth would be higher in the wider spacing and wood density would be higher in the narrower spacing. The diameter growth of trees was higher at 3 m × 2.5 m than at 3 m × 2 m and 3 m × 1.5 m. Nevertheless, this higher individual tree growth at 3 m × 2.5 m did not compensate for the greater tree stock density at 3 m × 1.5 m with stand stemwood production at 38 years of 530 m3 ha^?1 and 649 m³ ha^?1, respectively. These results suggest that C. legalis, which can produce up to 17 m³ ha^?1 y^?1 of medium-to high-density timber – about 800 kg m^?3 – is a promising native species for forest plantations in Brazil.  相似文献   

Assessing carbon sequestration in plantation forests of important conifers based on the system of permanent sample plots across Taiwan     

Tian-Ming Yen  Kai-Luo Huang  Long-En Li  Chao-Huan Wang 《Journal of Sustainable Forestry》2020,39(4):392-406

ABSTRACT

Plantation forests play a critical role in forest management due to their high productivity and large contribution to carbon sequestration (CSE). The purpose of this study was to assess the CSE of plantations containing four important conifer species distributed across Taiwan, namely, the China fir (Cunninghamia lanceolata), Japanese cedar (Cryptomeria japonica), Taiwania (Taiwania cryptomerioides) and Taiwan red cypress (Chamaecyparis formosensis). Data regarding the plantations were obtained from a survey of permanent sample plots (PSPs). We used these data to calculate the CSE in each PSP and adopted CSE_mean and CSE_period as indicators to assess the CSE of the four conifers. According to the CSE_mean obtained from analysis of variance and the least significant difference method, two groups were identified among these four conifers: the Japanese cedar (4.03 Mg ha^?1 yr^?1) and Taiwania (3.52 Mg ha^?1 yr^?1) yielded higher CSE_mean values and the China fir (1.79 Mg ha^?1 yr^?1) and Taiwan red cypress (2.36 Mg ha^?1 yr^?1) yielded lower CSE_mean values. The same patterns were observed in the CSE_period values; however, no significant difference in CSE_period was observed between Taiwan red cypress and either of the two groups. Therefore, Japanese cedar and Taiwania have high CSE potential among conifers.  相似文献   

Bioenergy production and soil conservation from Norway spruce (Picea abies L. Karst) plantations in Denmark     

Rasoul Yousefpour 《Agroforestry Systems》2013,87(2):287-294

This study analyses the trade-off between bioenergy production and soil conservation through thinning operations in Norway spruce (Picea abies L. Karst) plantations in Denmark. Thinning operations were evaluated under different regimes and intensities for a complete rotation period of sixty years and for different site qualities (site-classes I–VI). Applying a dynamic forest growth modeling tool, evolution of forest structure was predicted to observe the potentials for biomass production and inevitable soil degradation. Results showed thinning from below, with a higher utilization (maintenance of a minimum basal area of 25 m² ha^?1) could produce more bioenergy. However, these operations require simultaneous severe forest soil degradation. Therefore, the optimum thinning for bioenergy production under preservation constraints was thinning from above with a lower intensity (maintenance of a minimum basal area of 45 m² ha^?1). The ratio of bioenergy win (kWh) to soil-loss (m³ ha^?1) was calculated for this regime varying between 74,894 kWh m^?3 in a high quality site (site-class I) and 6,516 kWh m^?3 in a low quality site (site-class VI) with an average of 44,282 kWh m^?3. However, this could not always preserve the highest amount of growing stock essential for natural dynamics of forest ecosystem with an exception of the low quality sites (site-class VI). Thus, when aiming at bioenergy production through thinning operations, trade-offs with soil conservation and growing stock preservation should be regarded to prevent environmental degradation.  相似文献   

Carbon dynamics and stability between native Masson pine and exotic slash pine plantations in subtropical China     

Zeqing Ma  Henrik Hartmann  Huimin Wang  Qingkang Li  Yidong Wang  Shenggong Li 《European Journal of Forest Research》2014,133(2):307-321

Afforestation and ecological restoration have often been carried out with fast-growing exotic tree species because of their high apparent growth and yield. Moreover, fast-growing forest plantations have become an important component of mitigation measures to offset greenhouse gas emissions. However, information on the long-term performance of exotic and fast-growing species is often lacking especially with respect to their vulnerability to disturbance compared to native species. We compared carbon (C) storage and C accumulation rates in vegetation (above- and belowground) and soil in 21-year-old exotic slash pine (Pinus elliottii Engelm.) and native Masson pine (Pinus massoniana Lamb.) plantations, as well as their responses to a severe ice storm in 2008. Our results showed that mean C storage was 116.77 ± 7.49 t C ha^?1 in slash pine plantation and 117.89 ± 8.27 t C ha^?1 in Masson pine plantation. The aboveground C increased at a rate of 2.18 t C ha^?1 year^?1 in Masson pine and 2.23 t C ha^?1 year^?1 in slash pine plantation, and there was no significant difference in C storage accumulation between the two plantation types. However, we observed significant differences in ice storm damage with nearly 7.5 % of aboveground biomass loss in slash pine plantation compared with only 0.3 % loss in Masson pine plantation. Our findings indicated that the native pine species was more resistant to ice storm because of their adaptive biological traits (tree shape, crown structure, and leaf surface area). Overall, the native pine species might be a safer choice for both afforestation and ecological restoration in our study region.  相似文献