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1.
Replantation of degraded forest using rapidgrowth trees can play a significant role in global carbon budget by storing large quantities of carbon in live biomass,forest floor,and soil organic matter.We assessed the potential of 20-year old stands of three rapid-growth tree species,including Alnus subcordata,Populus deltoides and Taxodium distichum,for carbon(C) storage at ecosystem level.In September 2013,48 replicate plots(16 m × 16 m) in 8 stands of three plantations were established.36 trees were felled down and fresh biomass of different components was weighed in the field.Biomass equations were fitted using data based on the 36 felled trees.The biomass of understory vegetation and litter were measured by harvesting all the components.The C fraction of understory,litter,and soil were measured.The ecosystem C storage was as follows: A.subcordata(626.5 Mg ha~(-1)) [ P.deltoides(542.9Mg ha~(-1)) [ T.distichum(486.8 Mg ha~(-1))(P \ 0.001),of which78.1–87.4% was in the soil.P.deltoides plantation reached the highest tree biomass(206.6 Mg ha~(-1)),followed by A.subcordata(134.5 Mg ha~(-1)) and T.distichum(123.3 Mg ha~(-1)).The highest soil C was stored in theplantation of A.subcordata(555.5 Mg ha~(-1)).The C storage and sequestration of the plantations after 20 years were considerable(25–30 Mg ha~(-1) year~(-1)) and broadleaves species had higher potential.Native species had a higher soil C storage while the potential of introduced species for live biomass production was higher. 相似文献
2.
We studied leaf litter fall, decomposition and nutrient release patterns of Shorea robusta and Tectona grandis by using a litter bag technique to better understand the release pattern of nutrients to soil from leaf litter. Annual litterfall varied from 13.40 ± 2.56 t ha?1 a?1 for S. robusta to 11.03 ± 3.72 t ha?1 a?1 for T. grandis and the decay constant (k) of decomposed leaf litter was distinctly higher for T. grandis (2.70 ± 0.50 a?1) compared to S. robusta (2.41 ± 0.30 a?1). Biomass loss was positively correlated with the initial litter C, WSC, C/N and ash content in S. robusta and N, P and K concentration for T. grandis. Biomass was negatively correlated with lignin and L/N ratio for S. robusta and L, WSC, L/N and C/N ratio for T. grandis (P < 0.01). Nutrient use efficiency (NUE) and nutrient accumulation index (NAI) of S. robusta was higher than for T. grandis. The retranslocation of bioelements from senescent leaves ranked as P > N > K. Annual N, P and K input to soil through litterfall differed significantly between the two species in the following order: N>K>P. S. robusta was superior in terms of K and P return and T. grandis was superior in terms of N return. The two tree species showed a similar patterns of nutrient release (K > P > N) during decomposition of their leaf litter. Nutrients of N, K and P were the primary limiting nutrients returned to soil through litterfall with important roles in soil fertility and forest productivity. 相似文献
3.
Jan Suszka Beata P. Plitta Marcin Michalak Barbara Bujarska-Borkowska Tadeusz Tylkowski Paweł Chmielarz 《Annals of Forest Science》2014,71(5):543-549
Context
Black poplar (Populus nigra L.) is an alluvial forest tree species whose genetic pool is decreasing in Europe. Poplar trees produce short-lived seeds that do not store well.Aim
The feasibility of seed storage in conventional and cryogenic conditions after their desiccation from water content (WC) of 0.15 to 0.07 g H2O g?1 dry mass (g g?1) was investigated.Methods
Seed germinability was evaluated (seeds with a radicle and green cotyledons were counted) after storage of seeds for a period of 3 to 24 months at different temperatures: 20°, 10°, 3°, ?3°, ?10°, ?20° or ?196°C.Results
Seeds desiccated to a 0.07 g g?1 WC can be stored successfully at ?10 °C and ?20 °C for at least 2 years. A significant decrease in germination was observed only after 12 months of seed storage (WC 0.15 g g?1) at temperatures above 0 °C. We demonstrated that both fresh (0.15 g g?1 WC) and desiccated (0.07 g g?1 WC) seeds can be preserved at ?196 °C for at least 2 years.Conclusions
Seed storage temperature and time of storage were statistically significant factors affecting seed storability. The presented data provide a foundation for the successful gene banking of P. nigra seeds. 相似文献4.
? Context
Harsh environmental conditions in xeric sites of Andean Patagonia, affect the emergence, survival, and growth of either naturally grown or planted Austrocedrus seedlings.? Aims
We evaluated the effects of nurse shrubs and tree shelters on the survival and growth of Austrocedrus seedlings as compared to unprotected (control) areas and how differently produced seedling types perform under these treatments.? Methods
In 2006, two Austrocedrus seedling types (1?+?2?=?S1 and Plug 2?+?1?=?S2) were planted under shrub cover (C1), tree shelter (C2), and control (C3). Soil surface temperature and moisture were measured for each treatment during the first growing season, while seedling survival and height were recorded during 5 years.? Results
Survival was not affected by cover type the first year, but it was affected by seedling type (S1?>?S2). After an extremely dry second growing season, seedling survival significantly decreased in relation to either cover or seedling type. Five years after plantation, survival was significantly higher for C1 and C2 (40?C60 %) as compared to C3-S2 (18 %). Seedling height was significantly affected by cover, but not by seedling type.? Conclusions
The use of nurse shrubs and/or tree shelters is useful in Austrocedrus seedling restoration trials. Seedling morphology appears as relevant for survival in semiarid environments. 相似文献5.
6.
? Context
The rising demand of energy wood for heating purposes in Germany leads to concerns regarding the overexploitation of forests. A major aspect is the impact of whole-tree harvesting on long-term productivity of forest soils.? Aims
This study aimed to analyze the effects of nutrient removal on productivity using the historically prevalent practice of litter raking. Since there is a lack of controlled whole-tree harvesting experiments in Germany, we used litter raking as a surrogate management practice entailing the removal of nutrients from forest stands.? Methods
We used three sites with documented litter raking to analyze the effects of nutrient removal on productivity using dendroecological methods: two recent litter removal experiments in two Scots pine stands (Siegenburg and Burglengenfeld) and one oak stand (Eichhall) with documented historic litter raking. Basal area increment (BAI) and tree-ring characteristics were compared between periods with litter raking and the preceding periods for both treatment and control plots.? Results
For the two Scots pine sites with a relatively short litter raking period, no effects of litter raking on BAI could be ascribed to nutrient removal. On the oak site with a longer history of litter utilization, the loss in BAI due to litter raking amounts to 22 % during the period with active raking and to still 17 % in the recovery period.? Conclusions
These results contribute to the still very limited understanding about the impact of whole-tree harvesting on forest productivity in Germany by laying down an upper limit of possible effects due to nutrient removal, as nutrient loss by litter raking tends to be higher than nutrient loss by whole-tree harvesting. 相似文献7.
Responses of labile soil organic carbon and enzyme activity in mineral soils to forest conversion in the subtropics 总被引：1，自引：0，他引：1
Aims
Globally, extensive areas of native forest have been almost replaced by plantations to meet the demands for timber, fuel material and other forest products. This study aimed to evaluate the effects of forest conversion on labile soil organic C (SOC), soil respiration, and enzyme activity, and to quantify their relationship in subtropical forest ecosystems.Methods
Surface mineral soil (0–20 cm) was collected from a Cunninghamia lanceolata Hook. plantation, Pinus massoniana Lamb. plantation, Michelia macclurei Dandy plantation, and an undisturbed native broadleaf forest. Soil microbial biomass C, dissolved organic C, permanganate-oxidizable C, basal respiration, and six enzyme activities were investigated.Results
Soil microbial biomass C was higher by 45.9 % in native broadleaf forest than that in M. macclurei Dandy plantation. The ratio of soil microbial biomass C to total SOC was 27.6 % higher in the M. macclurei Dandy plantation than in the native broadleaf forest. The soil respiration increased by 25.2 % and 21.7 % after conversion from native broadleaf forest to P. massoniana Lamb. and M. macclurei Dandy plantations respectively. The effects of forest conversion on the soil enzyme activities differed among the tree species. Soil microbial biomass C had higher correlation with soil respiration than with the other SOC fractions. Moreover, soil microbial biomass C was positively correlated with urease and negatively correlated with cellulase activity. Soil respiration had higher correlation with soil microbial biomass C, dissolved organic C and permanganate-oxidizable C.Conclusion
Forest conversion affected the soil microbial biomass C, soil respiration, invertase, cellulase, urease, catalase, acid phosphatase, and polyphenol oxidase activities, but their response depended on tree species. Soil respiration was mainly controlled by labile SOC, not by total SOC. 相似文献8.
Jianfen Guo Guangshui Chen Jinsheng Xie Zhijie Yang Yusheng Yang 《Annals of Forest Science》2014,71(5):585-594
? Context
Coarse woody debris (CWD, ≥10 cm in diameter) is an important structural and functional component of forests. There are few studies that have estimated the mass and carbon (C) and nitrogen (N) stocks of CWD in subtropical forests. Evergreen broad-leaved forests are distributed widely in subtropical zones in China.? Aims
This study aimed to evaluate the pools of mass, C and N in CWD in five natural forests of Altingia gracilipes Hemsl., Tsoongiodendron odorum Chun, Castanopsis carlesii (Hemsl.) Hayata, Cinnamomum chekiangense Nakai and Castanopsis fabri Hance in southern China.? Methods
The mass of CWD was determined using the fixed-area plot method. All types of CWD (logs, snags, stumps and large branches) within the plot were measured. The species, length, diameter and decay class of each piece of CWD were recorded. The C and N pools of CWD were calculated by multiplying the concentrations of C and N by the estimated mass in each forest and decay category.? Results
Total mass of CWD varied from 16.75 Mg ha?1 in the C. fabri forest to 40.60 Mg ha?1 in the A. gracilipes forest; of this CWD, the log contribution ranged from 54.75 to 94.86 %. The largest CWD (≥60 cm diameter) was found only in the A. gracilipes forest. CWD in the 40–60 cm size class represented above 65 % of total mass, while most of CWD accumulations in the C. carlesii, C. chekiangense and C. fabri forests were composed of pieces with diameter less than 40 cm. The A. gracilipes, T. odorum, C. carlesii and C. chekiangense forests contained the full decay classes (from 1 to 5 classes) of CWD. In the C. fabri forest, the CWD in decay classes 2–3 accounted for about 90 % of the total CWD mass. Increasing N concentrations and decreasing densities, C concentrations, and C:N ratios were found with stage of decay. Linear regression showed a strong correlation between the density and C:N ratio (R 2?=?0.821). CWD C-stock ranged from 7.62 to 17.74 Mg ha?1, while the N stock varied from 85.05 to 204.49 kg ha?1. The highest overall pools of C and N in CWD were noted in the A. gracilipes forest.? Conclusion
Differences among five forests can be attributed mainly to characteristics of the tree species. It is very important to preserve the current natural evergreen broad-leaved forest and maintain the structural and functional integrity of CWD. 相似文献9.
? Key message
The optimal management of larch (Larix olgensis) plantations in Northeast China consisted of 2 or 3 thinnings and a rotation length of 55–61 years when economic profitability, wood production, and carbon sequestration were simultaneously maximized. Wood production ranged from 5.4 to 11.7 m3 ha?1 a?1, depending on site quality.? Context
L. olgensis is an important tree species in the northeast forest region of China, playing a significant role in the establishment of fast-growing and high-yielding plantation forests in China. However, the management of these plantations has not been optimized in previous studies.? Aims
The objective of the study was to find the optimal combinations of thinning times, thinning types, and rotation length for L. olgensis stands when both timber production and carbon stock are considered.? Methods
First, a growth and yield model was developed to simulate the dynamics of larch plantations. Then, the models were linked with the Hooke and Jeeves optimization algorithm to optimize forest management for two commonly used planting densities and three site qualities.? Results
Two thinnings were found to be suitable for larch plantations when the stand density at 10 years was 2125 trees/ha (corresponding to a planting density of 2500 trees/ha) whereas three thinnings were recommended when the density at 10 years was 2800 trees/ha (planting density of 3300 trees/ha). When the stand density was 2800 trees/ha, the optimal rotation length was 61, 58, and 55 years for site indices (SI) 12, 16, and 20 m (dominant height at 30 years), respectively. The mean annual wood production was 5.4 m3 ha?1 for SI 12, 8.2 m3 ha?1 for SI 16, and 11.7 m3 ha?1 for SI 20. The results were nearly the same for the lower initial stand density. The better the site quality of the stand, the earlier the thinnings were conducted.? Conclusion
In multifunctional forestry, optimal rotation lengths of larch plantations were 10–20 years longer than advised in the current silvicultural recommendations for Northeast China.10.
? Context
Soil temperature can limit tree growth and function, but it is often unaddressed in understanding the successional status of trees.? Aims
We tested how soil temperature affected carbon allocation strategies of two dominant co-occurring boreal conifer species, Pinus contorta and Picea mariana.? Methods
We measured nonstructural carbon (NSC) concentrations, biomass, and photosynthesis of dormant and actively growing 2-year-old seedlings in response to three soil temperatures (5, 10, and 20 °C) under a common ambient air temperature.? Results
For both species, variation in carbon reserves with soil temperature was more pronounced following seedling growth than during dormancy. For both species and all organ types (roots, needles, and stems), NSC concentrations were highest when seedlings were grown at 5 than 20 °C. Mass adjusted for NSC content was negatively correlated with NSC concentration for all organ types of both species. Soil temperature had a marginally significant effect on photosynthesis of pine; seedlings grown at 10 or 20 °C acquired more carbon than seedlings grown at 5 °C. Spruce seedlings photosynthesized more when grown at 20 °C than at 5 or 10 °C.? Conclusion
Interspecific differences in allocation of carbon may underlie the responses of P. mariana and P. contorta to cold soils and consequently their successional status. 相似文献11.
Root biomass plays an essential role in carbon sequestration at both individual and ecosystem scales, yet few feasible methods for measuring root biomass of individual trees have been developed. We sampled 11 trees in a pure 20-year-old Pinus tabuliformis plantation to estimate total root, fine root and leaf biomass of individual trees using the nested regression method. The relationships between fine root biomass and surface area as well as leaf biomass and area were examined across tree sizes. Fine roots of P. tabuliformis were estimated to consume 40 % of the net primary production for turnover, and absorbed a total of 1364 g m?2 year?1 of major nutrients. A significant linear relationship was determined between roots and leaves in terms of both biomass and surface area. The findings added weight to the concept that the functional balance theory is applicable to even-aged mature trees of P. tabuliformis. 相似文献
12.
Xiaoxi Zhang Zengwen Liu Bochao Zhu Yuanhao Bing Nhu Trung Luc Liangzhen Du Zhenhua Zhu 《林业研究》2016,27(3):525-532
The productivity of Robinia pseudoacacia (R.p.) pure forest usually declines at the late growth stage, and reforming it into mixed forests could be a promising way to resolve this problem. When choosing a suitable tree species that can be mixed with R.p., the interspecific relationship is an important issue. Therefore, we gathered the autumn litter fall from R.p. and 10 other species from the Loess Plateau of China were mixed in dual species litterbags (R.p. + each other species) and buried them in soil for a 345 days lab decay incubation. We measured the litter mass loss and nutrient contents to determine whether the nutrient release was affected by mixed species litter decomposition. The impacts of mixed litter decomposition on macro-elements release were more obvious than on micro-elements. The litters with similar substrate quality might show variable impacts on nutrients release in mixed decomposition. The C loss and release of nutrient was improved by descending order when R.p. litter was mixed with Hippophae rhamnoides, Ulmus pumila, Populus simonii, Larix principis-rupprechtii and Quercus liaotungensis (Q.l.). But, except for Q.l., only the other species were recommended as suitable mix-plants for R.p. since promoting a high turnover of the nutrient in the litter compartment and a rapid availability for tree. 相似文献
13.
Understanding the impact of plant litters on soil nitrogen(N) dynamics could facilitate development of management strategies that promote plantation ecosystem function.Our objective was to evaluate the effects of different litter types on N mineralization and availability,microbial biomass, and activities of L-asparaginase and odiphenol oxidase(o-DPO) in soils of a poplar(Populus deltoides) plantation through 24 weeks of incubation experiments.The tested litters included foliage(F), branch(B), or root(R) of poplar trees, and understory vegetation(U) or a mixture of F, B, and U(M).Litter amendments led to rapid N immobilization during the first 4 weeks of incubation, while net N mineralization was detected in all tested soils from 6 to 24 weeks of incubation, with zeroorder reaction rate constants(k) ranging from 7.7 to9.6 mg N released kg~(-1) soil wk~(-1).Moreover, litter addition led to increased microbial biomass carbon(C) 49–128% and increased MBC:MBN ratio by 5–92%,strengthened activities of L-asparaginase and o-DPO by14–74%; Up to about 37 kg N ha~(-1) net increase in mineralized N in litter added soils during 24 weeks of incubation suggests that adequate poplar and understory litter management could lead to reduced inputs while facilitate sustainable and economic viable plantation production. 相似文献
14.
Jorge Olivar Stella Bogino Cyrille Rathgeber Vivien Bonnesoeur Felipe Bravo 《Annals of Forest Science》2014,71(3):395-404
? Context
Modification of stand density by thinning may buffer the response of tree growth and vigor to changes in climate by enhancing soil water availability.? Aims
We tested the impact of thinning intensity on cambial growth of Aleppo pine (Pinus halepensis L.) under semi-arid, Mediterranean conditions.? Methods
A multiple thinning experiment was established on an Aleppo pine plantation in Spain. We analysed the stem growth dynamics of two different crown classes under four different thinning intensities (15 %, 30 %, and 45 % removal of the basal area) for 2 years, based on biweekly band dendrometer recordings. Local relative extractable soil water was derived from the use of a water balance model Biljou© (available at https://appgeodb.nancy.inra.fr/biljou/) and used as an explanatory variable.? Results
Radial growth was mainly controlled by soil water availability during the growing season, and differed by crown class. The growth rates of dominant trees were significantly higher than the growth rates of suppressed trees. Removal of 30 % and 45 % of the initial basal area produced a growth release in both dominant and suppressed trees that did not occur under less intense thinning treatments.? Conclusions
Soil water availability was the main driver of radial growth during the growing season. Forest management confirmed its value for ameliorating the effects of water limitations on individual tree growth. These results may help managers understand how altering stand density will differentially affect diameter growth responses of Aleppo pine to short-term climatic fluctuations, promoting forests that are resilient to future climatic conditions. 相似文献15.
Douglas Godbold Arvo Tullus Priit Kupper Jaak Sõber Ivika Ostonen Jasmin A. Godbold Martin Lukac Iftekhar U. Ahmed Andrew R. Smith 《Annals of Forest Science》2014,71(8):831-842
Context
Anthropogenic activity has increased the level of atmospheric CO2, which is driving an increase of global temperatures and associated changes in precipitation patterns. At Northern latitudes, one of the likely consequences of global warming is increased precipitation and air humidity.Aims
In this work, the effects of both elevated atmospheric CO2 and increased air humidity on trees commonly growing in northern European forests were assessed.Methods
The work was carried out under field conditions by using Free Air Carbon dioxide Enrichment (FACE) and Free Air Humidity Manipulation (FAHM) systems. Leaf litter fall was measured over 4 years (FACE) or 5 years (FAHM) to determine the effects of FACE and FAHM on leaf phenology.Results
Increasing air humidity delayed leaf litter fall in Betula pendula, but not in Populus tremula?×?tremuloides. Similarly, under elevated atmospheric CO2, leaf litter fall was delayed in B. pendula, but not in Alnus glutinosa. Increased CO2 appeared to interact with periods of low precipitation in summer and high ozone levels during these periods to effect leaf fall.Conclusions
This work shows that increased CO2 and humidity delay leaf fall, but this effect is species-specific. 相似文献16.
Anne-Sophie Sergent Nathalie Bréda Léopoldo Sanchez Jean-Charles Bastein Philippe Rozenberg 《Annals of Forest Science》2014,71(6):709-720
Context
Since the 2003 drought and heat wave, Douglas-fir dieback has been reported in France in trees older than 30 years. Consequently, it is questioned whether selected Douglas-fir provenances are suited to the frequent and severe drought events which are forecast due to climate change.Aims
Our objective was to contribute to the screening of variability in productivity and growth response to soil-water deficit of mature trees from provenances not currently used for plantation in France.Methods
We sampled 22 provenances, including coastal and interior Douglas-fir, covering a wide part of its natural distribution, from Oregon to California for coastal provenances and from British Columbia to New Mexico for interior provenances. These provenances were planted at the mid 1970s in two provenance trials located in the south-west area of France. Variability of productivity, of wood density, and of radial growth in response to drought episodes among provenances was quantified and related to soil-water deficit computed by daily water balance calculations.Results
Whatever the provenance, annual radial growth is highly dependent on local soil-water deficit (Felines R 2 = 0.57, Le Treps R2 = 0.49). Radial growth and wood properties exhibit large differences between provenances at 30 years old. Variability between provenances for all wood characteristics studied is mainly structured geographically. Coastal provenances perform best for productivity at 30 years old (619 cm2?±?59), and exhibit a small growth reduction in 2004, the second successive year of drought (?10.7 %?±?3.8). Surprisingly, the southern interior provenances from the driest environments in the natural range show a large growth reduction in 2004 (?30.5 %?±?5.2).Conclusions
The provenances tested exhibited significant differences in growth performance and growth reduction induced by the soil-water deficit. The approach coupling retrospective analysis of radial growth on mature trees and water balance modelling is relevant for evaluating provenance adaptation to more frequent or severe drought episodes. 相似文献17.
Daniela Baldantoni Alessandro Bellino Fausto Manes Anna Alfani 《Annals of Forest Science》2013,70(6):571-578
Context
The evaluation of changes in litter decomposition rate due to increasing trend in tropospheric ozone is an emerging field of investigation, providing relevant information on long-term forest ecosystem sustainability.Aims
This research aims to clarify the effects of ozone exposure on Quercus ilex leaf chemical composition and decomposition slow down.Methods
Young plants were fumigated in growth chambers at a cumulative dose of 17.15 ppm h. To assess the fumigation effectiveness, stomatal conductance and net photosynthesis were monitored. Leaves were analysed for C, N, S, Ca, Mg, K, Fe, Zn, Mn, total soluble sugars, starch, acid-detergent fibre (ADF), lignin and cellulose prior to the incubation in litter bags in mesocosms, and during decomposition along 395 days.Results
Ozone-exposed leaves showed a significant reduction in net photosynthesis and stomatal conductance but did not differ from control leaves in all the chemical parameters analysed. Nevertheless, leaf decomposition rate was lower in treated leaves. The main differences between the models describing the mass loss in exposed and control leaves were played by ADF for exposed leaves and by lignin for control leaves, as well as by N, that showed a greater contribution in the model for the exposed leaves.Conclusion
Ozone fumigation of Q. ilex results in leaf litter decomposition slowing down, mainly due to ADF joint dynamics with the other variables describing mass decay, even if no detectable changes in initial leaf composition occur. 相似文献18.
The present study was an effort to understand the amount of litter fall and its subsequent decomposition and quantify the release of available nutrients and soil physicochemical characteristics in plantations of four forest tree species(Lagerstroemia parviflora, Tectona grandis, Shorea robusta and Michelia champaca) in the Chilapatta Reserve Forest of the Cooch Behar Wildlife Division in the Terai zone of West Bengal, India. The most litter(5.61 Mg ha~(-1))was produced by T. grandis plantation and the least(4.72 Mg ha~(-1)) by L. parviflora. The material turnover rate to the soil through decomposition from total litter was fastest during the first quarter of the year and subsequently decreased during the next two quarters. The material turnover rate was only 1 year, which indicates that more than90% of the total litter produced decomposed within a year.The available primary nutrient content in litter varied across the four plantations over the year. The plantations generally did not significantly influence the soil physical characteristics but did significantly influence the availability of primary nutrients and organic carbon at two depths(1–15 and16–30 cm) over the year. The availability of soil primary nutrients in the four plantations also increased gradually from the first quarter of the year to the third quarter and then decreased during the last quarter to the same level as in the first quarter of the year at both depths. The availability for soil organic carbon in the plantations followed a similar trend. The amount of litter produced and the material turnover in the soil in the different plantations differed, influencing the nutrient availability and organic carbon at the plantations. The amount of soil organic carbon was highest for T. grandis(2.52 Mg ha~(-1)) and lowest for L. parviflora(2.12 Mg ha~(-1)). Litter is the source of soil organic matter,and more the litter that is produced by the plantations, the higher will be the content and amount of soil organic carbon in the plantation. 相似文献
19.
Jean-Daniel Bontemps Pierre Gelhaye Gérard Nepveu Jean-Christophe Hervé 《Annals of Forest Science》2013,70(4):329-343
? Context
While historical increases in forest growth have been largely documented, investigations on historical wood density changes remain anecdotic. They suggest possible density decreases in softwoods and ring-porous hardwoods, but are lacking for diffuse-porous hardwoods.? Aims
To evaluate the historical change in mean ring density of common beech, in a regional context where a ring-porous hardwood and a softwood have been studied, and assess the additional effect of past historical increases in radial growth (+50 % over 100 years), resulting from the existence of a positive ring size–density relationship in broadleaved species.? Methods
Seventy-four trees in 28 stands were sampled in Northeastern France to accurately separate developmental stage and historical signals in ring attributes. First, the historical change in mean ring density at 1.30 m (X-ray microdensitometry) was estimated statistically, at constant developmental stage and ring width. The effect of past growth increases was then added to assess the net historical change in wood density.? Results
A progressive centennial decrease in mean ring density of ?55 kg?m?3 (?7.5 %) was identified (?10 % following the most recent decline). The centennial growth increase induced a maximum +25 kg?m?3 increase in mean ring density, whose net variation thus remained negative (?30 kg?m?3).? Conclusions
This finding of a moderate but significant decrease in wood density that exceeds the effect of the positive growth change extends earlier reports obtained on other wood patterns in a same regional context and elsewhere. Despite their origin not being understood, such decreases hence form an issue for forest carbon accounting. 相似文献20.
Laura Hernández Isabel Cañellas Iciar Alberdi Iván Torres Fernando Montes 《Annals of Forest Science》2014,71(2):161-171