共查询到20条相似文献，搜索用时 31 毫秒
1.
《Forest Ecology and Management》1999,113(1):11-21
A methodological approach to the identification of biodiversity indicators in commercial forest stands is illustrated by analysis of the relationships between syrphid (hoverflies) and carabid (ground beetles) community composition and diversity, and stand structure and field layer vegetation. Data were collected from 12 commercial forest sites encompassing a range of climatic conditions and different crop types (Scots pine, Sitka spruce, Norway spruce and Corsican pine) across the UK. Comparisons were also made between unmanaged semi-natural Scots pine woods and Scots pine plantations. For both syrphids and carabids, no differences in species richness and diversity were recorded between semi-natural stands and plantations; one rare syrphid considered to be restricted to semi-natural pine stands was also found in spruce. Syrphid species diversity and richness was higher in southern spruce sites than in the northern sites. Northern sites had distinctive carabid communities, as did sites in the New Forest, a large ancient woodland in southern England. Of the measured habitat variables, vertical stand structure showed the best correlation with species richness and diversity of both carabids and syrphids. Richness and diversity were less in stands with high vertical cover values for canopy layers. Stands with higher field layer cover supported greater syrphid diversity, but lower carabid diversity. Measures of stand structure could be used as potential indicators of syrphid and carabid diversity, but additional habitat parameters also need to be tested. 相似文献
2.
Elena Marcos Leonor Calvo José Antonio Marcos Ángela Taboada Reyes Tárrega 《European Journal of Forest Research》2010,129(1):25-30
We aimed to study tree effects on the chemical properties of forest soils. We compared soil features of three types of forest ecosystems, each with four stands (replicates): beech forests (Fagus sylvatica), oak forests (dominated by Quercus pyrenaica) and pine plantations (Pinus sylvestris). Five samples from the top 10 cm of soil were taken per stand, from which pH, organic matter content (O.M.), total nitrogen (N) and available calcium (Ca2+), magnesium (Mg2+), potassium (K+) and sodium (Na+) were determined. Litter layer depth was measured at each soil sampling point. We also measured tree density and crown diameters at each stand. Our results indicated that soil samples from the four pine plantation stands were more similar while oak and beech stands were characterised by great variability in terms of soil properties and leaf litter depth. Although the identity of the dominant tree species significantly influenced several topsoil chemical properties (increase in pH and available cations in oak forests and higher organic matter and total nitrogen in beech and pine ecosystems), there were other important factors affecting soil features that may be taken under consideration. Differences between soil properties of the three types of forest ecosystems were mainly related to the characteristics of the litter layer and less related to the tree layer structure. Finally, the establishment of pine plantations in naturally deciduous tree areas made the topsoil features more homogeneous. 相似文献
3.
To test the direct regeneration hypothesis and support natural disturbance-based forest management we characterized the structure and composition of boreal mixedwood forests regenerating after large wildfires and examined the influence of pre-fire stand composition and post-fire competing vegetation. In stands which had been deciduous (Populus sp.)-dominated, conifer (white spruce)-dominated, or mixed pre-fire we measured regeneration stocking (presence in 10 m2 plots), density and height 10–20 years post-burn in five wildfires in Alberta, Canada. Most plots regenerated to the deciduous or mixed stocking types; plots in the older fire and in stands that were pure conifer pre-fire had higher amounts of conifer regeneration. Surprisingly, regeneration in pre-fire ‘pure’ white spruce stands was most often to pine, although these had not been recorded in the pre-fire inventory. Pre-fire deciduous stands were the most resilient in that poplar species dominated their post-fire regeneration in terms of stocking, density and height. These stands also had the highest diversity of regenerating tree species and the most unstocked plots. High grass cover negatively affected regeneration density of both deciduous and conifer trees. Our results demonstrate the natural occurrence of regeneration gaps, pre- to post-fire changes in forest composition, and high variation in post-fire regeneration composition. These should be taken into consideration when developing goals for post-harvest regeneration mimicking natural disturbance. 相似文献
4.
In the north Saxon lowlands (near Torgau), effects of conversion of pure pine stands (Pinus sylvestris L.) into mixed stands by planting deciduous trees [Fagus sylvatica L. and Quercus petraea (Matt.) Liebl] were investigated on parasitoid wasps as pest antagonists. The effects of planting deciduous trees in pine stands were investigated using the strategy of space-for-time substitution including advanced plantations of beech and oak of different age classes. Wasps were captured at 4-week intervals by ground photoeclectors (GPE, n=6, 1 m2) and flight-interception traps (FIT, n=8), placed in the tree crown layer during the vegetation period (April–October) of 2000. A total of 32,479 parasitoid wasps belonging to 30 families were caught in the traps. Fifty-nine percent of individuals were representatives of families relevant as antagonists of forest insect pests: Ichneumonidae, Braconidae, Pteromalidae, Eulophidae, Mymaridae, Trichogrammatidae, and Scelionidae. Compared to the pure pine stand, individual numbers of most families of parasitoid wasps were statistically significantly higher in mixed stands with deciduous trees. The clearest promoting effects of deciduous trees on parasitoid wasps were manifested in the oldest age classes of advanced beech and oak plantations. Oak exerted stronger effects than beech. This applied especially to the tree crown layer, the stratum with the highest spatial correlation between important phytophagous pine pests and relevant parasitoids. The increased structural diversity of the stands and the broader spectrum of potential hosts are regarded as key factors for the promoting effects of advanced plantings of deciduous trees in pine stands on the community of parasitoid wasps. 相似文献
5.
Existing approaches for the assessment of forest management intensity lack a widely accepted, purely quantitative measure for ranking a set of forest stands along a gradient of management intensity. We have developed a silvicultural management intensity indicator (SMI) which combines three main characteristics of a given stand: tree species, stand age and aboveground, living and dead wooden biomass. Data on these three factors are used as input to represent the risk of stand loss, which is a function of tree species and stand age, and stand density, which is a function of the silvicultural regime, stand age and tree species. Consequently, the indicator consists of a risk component (SMIr) and a density component (SMId). We used SMI to rank traditional management of the main Central European tree species: Norway spruce (Picea abies [Karst.] L.), European beech (Fagus sylvatica L.), Scots pine (Pinus sylvestris L.), and oak (Quercus robur L. and Quercus petraea L.). By analysing SMI over their whole rotation period, we found the following ranking of management intensity: oak<beech<pine?spruce. Additionally, we quantified the SMI of actual research plots of the German Biodiversity exploratories, which represent unmanaged and managed forest stands including conifer forests cultivated outside their natural range. SMI not only successfully separate managed from unmanaged forests, but also reflected the variability of forest management and stand properties across the entire sample and within the different management groups. We suggest using SMI to quantify silvicultual management intensity of stands differing in species composition, age, silvicultural system (even-aged vs. uneven-aged), thinning grade and stages of stand conversion from one stand type into another. Using SMI may facilitate the assessment of the impact of forest management intensity on biodiversity in temperate forests. 相似文献
6.
Ángela Taboada Reyes Tárrega Leonor Calvo Elena Marcos José Antonio Marcos José María Salgado 《European Journal of Forest Research》2010,129(1):31-45
The aim of this study was to evaluate the influence of forest structure (mainly resulting from human uses) and forest type (the identity of the dominant tree species) on biodiversity. We determined the diversity of two taxonomical groups: the understory vegetation and the edaphic carabid beetle fauna. We selected eight types of forest ecosystems (five replicates or stands per forest type): pine (Pinus sylvestris) plantations of three age classes (10, 40 and 80 years since reforestation), an old-growth relict natural pine forest, and four types of oak (Quercus pyrenaica) stands: mature forests with livestock grazing and firewood extraction, mature forests where uses have been abandoned, “dehesa” ecosystems and shrubby oak ecosystems. The results obtained by a global PCA analysis indicated that both tree size and dominant species influenced the ordination of the 40 forest stands. In general, carabids were more sensitive to changes in forest heterogeneity and responded more clearly to the analysed structural variables than the understory vegetation, although the species richness of both groups was significantly correlated and higher in case of oak forests. Pine forest ecosystems were characterised by the lowest species richness for both taxonomical groups, the lowest plant diversity and by the lowest coefficients of variation and, consequently, low structural heterogeneity. As a result, it was very difficult to discriminate the effects of the spatial heterogeneity and the dominant tree species on biodiversity. 相似文献
7.
Carbon and nitrogen stocks and their medium-term and readily decomposable fractions in topsoils were compared in relation to soil microbial biomass and activity along sequences from coniferous to deciduous stands. The study was carried out in the Ore Mountains and the Saxonian lowland, representing two typical natural regions in Saxony, Germany. In accordance with current forest conversion practices, the investigation sites represent different stands: mature conifer stands of Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) (type A); Norway Scots spruce and pine with advanced plantings of European beech (Fagus sylvatica L.) or European beech/Common oak (Quercus petreae Liebl.) (type B); and mature deciduous stands of European beech and European beech/Common oak (type C). The investigated forest sites can be grouped into three silvicultural situations according to the development from coniferous stands to advanced plantings and finally mature deciduous forests (chronosequence A–B–C). The organic layer (L, F and H horizons) and uppermost mineral soil (0–10 cm) were analysed for potential C mineralisation, microbial biomass, concentrations of total C and N (TOC and TN) and for medium-term and readily decomposable C and N fractions, obtained by hot- and cold-water extraction respectively. The results showed an increase in organic layer thickness and mass as well as TOC and TN stocks along the forest sequences in the lowland. Yet, underplanted sites with two storeys revealed higher organic layer mass as well as TOC and TN stocks as compared to coniferous and deciduous stands. Stocks of hot- and cold-water-extractable C and N in relation to microbial biomass and its activity revealed a high turnover activity in deeper organic horizons of deciduous forests compared to coniferous stands. The stand-specific differentiation is discussed in relation to microbial biomass, litter quantity and quality and forest structure, but also with respect to the site-specific climatic factors and water budget as well as liming and fly-ash impacts. Results indicate higher dynamics in deciduous stands in the lowland especially during the initial turnover phase. The elevated microbial activity in deeper organic horizons of deciduous litter-influenced sites in spring is discussed as a specific indicator for long-term C sequestration potential as besides C mineralisation organic compounds are humified and thus, can be stored in the organic layer or in deeper soil horizons. Due to liming activities, stand-specific effects on organic matter turnover dynamics have evened out today in the Ore mountain region, but will presumably occur again once base saturation decreases. Here, the stand-specific effect on microbial biomass can currently be seen again as Cmic in the L horizon increased from spruce to beech. Our study sites in the lowland revealed no significant fly-ash impact. Differences between sites were evaluated by calculating the discriminance function. TOC and TN as well as medium-term degradable C and N were defined in this study as indicators for turnover dynamics along forest conversion sites. 相似文献
8.
Adoración Martínez Juan Carlos Iturrondobeitia Arturo Goldarazena 《Annals of Forest Science》2009,66(3):304-304
9.
Reyes Tárrega Leonor Calvo Ángela Taboada Elena Marcos José Antonio Marcos 《European Journal of Forest Research》2011,130(6):949-957
We compared the structure of the arboreal layer and the diversity and species composition of the understory vegetation of
three types of mature forest communities: oak (Quercus pyrenaica) and beech (Fagus sylvatica) forests and Scots pine (Pinus sylvestris) plantations. Our main aim was to determine whether differences in these variables existed and were due to the identity of
the dominant tree species. We selected four stands or replicates per forest type located geographically close and with relatively
similar conditions. We found no differences in the arboreal structure of oak and beech forests, which were characterised by
great variability in tree size, while in case of plantations, this variability was lower at both the intra-stand (estimated
by the coefficient of variation) and inter-stand (i.e. the four replicates harboured trees of similar sizes) scales. However,
the highest variability in the canopy layer of natural forests was not consistently linked to greater understory species richness.
Indeed, the lowest plant species richness was found in beech forests, while oak forests harboured the highest value at either
the sampling unit (per m2) or stand scales. The greatest negative correlation between plant diversity and the environmental variables measured was
found for litter depth, which was the highest in beech forests. The results obtained by the CCA indicated that the four replicates
of each forest type clustered together, due to the presence of characteristic species. We concluded that pine plantations
did not approach the environmental conditions of native forests, as plantations were characterised by singular understory
species composition and low arboreal layer variability, compared to natural woodlands. 相似文献
10.
《Scandinavian Journal of Forest Research》2012,27(1):53-61
This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland. 相似文献
11.
Plantations cover a substantial amount of Earth's terrestrial surface and this area is expected to increase dramatically in the coming decades. Pinus plantations make up approximately 32% of the global plantation estate. They are primarily managed for wood production, but have some capacity to support native fauna. This capacity likely varies with plantation management. We examined changes in the richness and frequency of occurrence of bird species at 32 plots within a Pinus radiata plantation (a management unit comprising multiple Pinus stands) in south-eastern Australia. Plots were stratified by distance to native forest, stand age class and thinning regime. We also assessed the landscape context of each plot to determine relationships between bird assemblages and stand and landscape-level factors. Bird species richness was significantly higher at plots ≥300 m from native forest and in mature (∼20 years since planting) and old (∼27 years since planting) thinned pine stands. We were able to separate the often confounding effects of stand age and thinning regime by including old stands that had never been thinned. These stands had significantly fewer species than thinned stands suggesting thinning regime, not age is a key factor to improving the capacity of pine plantations to support native species (although an age × thinning interaction may influence this result). At the landscape level, species richness increased in pine stands when they were closer to native riparian vegetation. There were no significant differences in species composition across plots. Our study indicates the importance of stand thinning and retention of native riparian vegetation in improving the value of pine plantations for the conservation of native fauna. 相似文献
12.
The aim of this study is to investigate the effects of forest conversion on forest floor vegetation. ‘Ecological’ forest conversion,
as defined by an interdisciplinary southern Black Forest project group, describes the transformation of even-aged spruce (Picea abies L. H. Karst.) stands to structured continuous cover forests consisting of spruce (Picea abies), silver fir (Abies alba Mill.) and beech (Fagus sylvatica L.). In order to analyse the conversion process, four conversion stages were defined in a conceptual forest development model.
Four forest districts deemed to be representative of the southern Black Forest region were selected for the study. The ground
vegetation was initially classified independently from the stand structures. Subsequently, the relationship between stand
structures, as determined by development stage, and ground vegetation was analysed. It was revealed that forest conversion
modified the ground vegetation. The main factors influencing ground vegetation were the influence of broadleaves, predominately
beech (F. sylvatica), on the canopy composition and litter coverage on the one hand; and the canopy coverage of spruce, the proportion of needle
litter and the associated light penetration on the other. The prevalence of moss and vascular plant species preferring acidic
sites found in spruce forests decreased during the transition process, whereas, species requiring a moderate base supply increased
in abundance. The continuous cover forest representing the final stage of conversion increasingly contained a mixture of ground
vegetation species normally associated exclusively with either conifer or deciduous forest. Due to the fact that there is
an associated ground vegetation specific to the different stages of forest conversion in stands dominated by Norway spruce
or European beech and a mixture in the latest conversion stages, large-scale forest conversion should be avoided in favour
of management promoting a diversity of silvicultural goals and treatments in neighbouring stands. Only a variety of treatments
ensures the maintenance of floristic diversity in the long-term. 相似文献
13.
The ecological effects of planting exotic Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] in Central Europe are still poorly understood. The aim of this study was to answer the question of whether Douglas-fir affects tree specific arthropod communities in different mature forest types (Douglas-fir, spruce and beech dominated) in Southern Germany. Therefore, arthropod communities of stem and tree crown strata of Douglas-fir and spruce (Picea abies L.) were sampled in the years 1999–2001 using arboreal photo-eclectors and flight interception traps. Statistical analysis was conducted for all species and focused on conifer specialists at three levels: (1) species diversity, (2) guild structure and (3) community structure. Within the stem stratum, species diversity was significantly higher on spruce than on Douglas-fir independent of year and stand composition. This could not be explained by a single feeding guild, rather by species changing strata during the vegetation period. In contrast, species diversity in tree crowns was approximately the same for both conifer species. However, communities in Douglas-fir crowns were conspicuously different from those in spruce crowns, especially in the Douglas-fir dominated stand type. While zoophagous insects exhibited higher activity on Douglas-fir in 2000, xylophagous beetles were more abundant on spruce in 2001. In European beech stands with widely spaced Douglas-fir trees, the site specific and broad-leaved tree related fauna might be maintained. In addition, Douglas-fir with its resource of Adelges cooleyi and crowns that overtop the broad-leaved tree canopy, offer additional resources for several aphidophagous and thermophile species. 相似文献
14.
Fyodor A. Tatarinov Emil CiencialaPetr Vopenka Vitaliy Avilov 《Forest Ecology and Management》2011,262(10):1919-1927
The simulation of forest production until 2100 under different environmental scenarios and current management practices was performed using a process-based model BIOME-BGC previously parameterized for the main Central-European tree species: spruce, pine, beech and oak and adapted to include forest management practices. Climatic scenario HadCM3 used in the simulations was taken from the IPCC database created within the 3rd Assessment Report. It was combined with a scenario of CO2 concentration development and a scenario of N deposition. The control scenario considered no changes of climatic characteristics, CO2 concentration and N deposition. Simulation experiment was performed for the test region - South Bohemia - using a 1 km × 1 km grid. The actual data on the regional forest cover were aggregated for each grid cell in such a way that each cell represented an even-aged single-dominant species stand or non-forested area, and a standard management scenario depending on the stand age and species was applied to each cell. The effect of environmental variables was estimated as the difference of simulated carbon pools and fluxes in 2050 under environmental changes and under control scenario.The model simulation for the period to 2050 with only climate change under constant CO2 concentration and N deposition indicated a small decrease of NPP (median values by species reached −0.9 to −1.7% for different species), NBP (−0.3 to −1.7%) and vegetation carbon (−0.3 to −0.7%), whereas soil C slightly increased. Separate increase of N deposition gave small positive effect on carbon pools (0.8-2.9% for wood C and about 0.5% for soil C) and more expressed effect on carbon fluxes (1.8-4.3% for NPP and 1.0-9.7% for NBP). Separate increase of CO2 concentration lead to 0.6-2.4% increase of wood C pool and 0.1-0.5% increase of soil C. The positive effects of CO2 concentration and N deposition were more pronounced for coniferous than for deciduous stands.Replacement of 0.5% of coniferous plantations every year by natural broadleaved stands evoked 10.5% of increase of wood carbon pool due to higher wood density of beech and oak compared to spruce and pine, but slightly decreased soil and litter carbon pools. 相似文献
15.
A comparison of plant and carabid beetle communities in an Irish oak woodland with a nearby conifer plantation and clearfelled site 总被引：8，自引：0，他引：8
In 1996, plant and carabid beetle communities were examined in a semi-natural oak woodland (Derryclare Wood) and compared with communities of a nearby mature conifer plantation and a plantation clearfelled in 1994. At each site, 10 quadrats (2 m×2 m) and 10 pitfall traps were used to sample the ground vegetation and carabid beetle communities, respectively. Forty-one plant species were recorded in the oak woodland while 38 species were found in the clearfelled site and 19 species in the conifer plantation. The median plant-species richness per quadrat was significantly greater (p<0.01) in the oak woodland (16.5) than in the other two sites and the clearfelled site (11) was significantly more species-rich (p<0.02) than the conifer plantation (6.5). A total of 21 carabid species (895 individuals) were captured, with 74.5, 13.9 and 11.6% of individuals being caught at the oak woodland, clearfelled site and conifer plantation, respectively. The median number of carabid species per pitfall trap was significantly greater (p<0.01) in the oak woodland (6) than in the clearfelled site (3.5) and conifer plantation (2). In addition, median species richness per pitfall trap was significantly higher in the clearfelled site than in the conifer plantation at p<0.02. Median diversity per pitfall trap was also significantly less in the conifer plantation (1.19) than in the oak woodland (2.43, p<0.01) and clearfelled site (1.55, p<0.05). While the Sorenson similarity index for both vegetation and carabids shows that the conifer plantation and the clearfelled site were most similar in species composition; nevertheless, the clearfelled site has demonstrated signs of increasing species richness only 2 years after clearfelling. It is concluded that while semi-natural woodlands support a greater range of species than conifer plantations, clearfelled areas which are not replanted can enhance species richness within commercial conifer plantations. 相似文献
16.
17.
Associations between Forest Type and Invertebrates: Ground Beetle Community Patterns in a Natural Oakwood and Juxtaposed Conifer Plantations 总被引：1，自引：0，他引：1
The character of carabid communities in juxtaposed conifer plantationand natural oak woodland was assessed and each found to be quitedistinctive. Distinctions arose from the differential abundanceof species and a lower species number in the natural oak woodland.Species at sample sites in the oak woodland, occurred with atleast equal frequency at sites in the conifer plantations. Therelatively species rich communities of ground beetles in areasafforested with conifers may have been derived partly from uplandblanket peat and heath, and partly from older woodland. At thetransition zone between the two main woodland types there wasan abrupt change in community character but none of the changesin species abundance could be interpreted as being detrimentalto the quality of carabid fauna in the oak woodland. 相似文献
18.
Using the physiological single tree growth model BALANCE, vitality of forest stands was simulated in dependence of the site-related
factors, climate and stand structure. At six level II plots in southern Germany with the main tree species beech (Fagus sylvatica L.), oak (Quercus robur L.), spruce (Picea abies [L.] Karst.), and pine (Pinus sylvestris L.), simulated results were compared to measured values (soil water content, bud burst and leaf colouring, diameter at breast
height, tree height and crown density) in order to validate the model. Sensitivity tests were done to examine the influence
and the interactions of the environmental parameters. The validation results show that BALANCE is capable of realistically
simulating the growth and vitality of forest stands for central European regions for medium term time spans (several years).
The validation of the water balance module produces mean absolute errors based on field capacity between 2.7 and 6.9% in dependence
of sites and forest stands. Senescence of foliage as well as crown density is reproduced with a correlation coefficient of
0.70 compared to measurements. Differences between measured and simulated diameter values were smaller than 1% for spruce
and smaller than 6.5% for beech after 7 years of simulation, and smaller than 1% for oak after 8 years of simulation. On the
other hand, the simulations for pine trees conform less with the measurements (difference: 22.6% after 8 years). The sensitivity
of the model on environmental changes and on combinations of these parameters could be demonstrated. The responses of the
forest stands were quite different. 相似文献
19.
This paper summarises the results from 35 years-observed thinning experiments on 256 permanent sample plots in 10–60 year-old
stands of ash, aspen, birch, oak, pine and spruce in Lithuania. Thinning enhanced crown projection area increment of residual
trees. The largest effect was observed in stands of aspen and birch (growth increase by 200%), followed by ash and oak (over
100%), and spruce and pine (about 80%). Thinning also promoted dbh increment, especially in younger stands, and the increase
of dbh increment was positively correlated with the thinning intensity. The strongest reaction was exhibited by oak and aspen,
while ash, birch and conifers reacted to a lower extent. Low and moderate intensities of thinning stimulated volume production
in younger stands while the opposite was observed in older stands with increasing removals. Spruce stands exhibited relatively
strongest increase of volume increment and pine, –the weakest, while the effect on deciduous species was intermediate. The
results demonstrate that significant increase in volume increment is achievable with thinning of only young forest stands,
e.g. 10–20 year-old pine, birch and ash, or 10–30 year-old oak, aspen and spruce. 相似文献
20.
Gunnar Thelin Ulrika Rosengren Ingeborg Callesen Morten Ingerslev 《Forest Ecology and Management》2002,160(1-3):115-125
Atmospheric deposition of N and S appears to have caused nutrient imbalance in Norway spruce stands in southern Sweden. This calls for a change of forest management to procedures that promote nutrient balance. Studies have shown lower soil acidity in Norway spruce/deciduous mixed stands than in spruce monocultures, but the tree nutrient status in such mixtures has not been much investigated so far.
The nutrient status of Norway spruce foliage and top mineral soil chemistry in monocultures and in stands mixed with beech, birch, or oak was investigated through paired comparisons on 30 sites in southern Sweden (27 sites) and eastern Denmark (three sites). In total, 45 mixed stands and 34 pure stands were included in the study.
Spruce needles from mixed stands had higher concentrations and ratios to N of K, P, and Zn than needles from pure spruce stands. Among the mixed stands, the K status appeared to be positively correlated with the percentage of deciduous tree basal area. Soil samples from mixed stands had a higher Mg concentration, base saturation, and BC/Al ratio than soil samples from pure stands. The spruce needle nutrient status was comparable in pure stands on fertile sites and in mixed stands on poor sites. We did not detect any differences in spruce tree growth between pure and mixed stands.
This paper discusses possible reasons for a positive effect on the tree nutrient status in mixed-species stands and the possibility of using mixed-species stands as a forest management procedure to avoid nutrient imbalance. 相似文献