Structure Of Natural Forests Research Articles

思茅松天然林树冠结构模型研究

PDF HTML阅读 XML下载 导出引用 引用提醒 思茅松天然林树冠结构模型 DOI: 10.5846/stxb201305301234 作者: 作者单位: 东北林业大学林学院 哈尔滨,西南林业大学西南地区生物多样性保育国家林业局重点实验室 昆明,西南林业大学西南地区生物多样性保育国家林业局重点实验室 昆明,西南林业大学西南地区生物多样性保育国家林业局重点实验室 昆明,西南林业大学西南地区生物多样性保育国家林业局重点实验室 昆明 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31160157）；云南省应用基础研究计划项目（2012FD027） Modeling tree crown structure of Simao pine (Pinus kesiya var. langbianensis) natural forest Author: Affiliation: School of Forestry,Northeast Forestry University,Key Laboratory of Biodiversity Conservation in Southwest China of State Forest Administration,Southwest Forestry University,Key Laboratory of Biodiversity Conservation in Southwest China of State Forest Administration,Southwest Forestry University,Key Laboratory of Biodiversity Conservation in Southwest China of State Forest Administration,Southwest Forestry University,Key Laboratory of Biodiversity Conservation in Southwest China of State Forest Administration,Southwest Forestry University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以云南省普洱市思茅区思茅松天然林为研究对象，采用枝解析调查了34株思茅松样木的树冠数据，分析了一级枝枝长、枝径、着枝角度、弦长和树冠半径5个树冠形状变量的变化规律，分别构建其预估模型；分析了树冠结构变化，分别构建了一级枝轮枝高度预估模型、一级枝枝条数量预估模型和一级枝枝条数量累积预估模型，并采用独立样本进行模型统计精度检验。结果表明：8个预估模型的预测效果良好，精度达到91%以上，尤其是一级枝着枝角度模型和一级枝轮枝高度模型预测精度达到97%以上。研究结果合理准确描述思茅松树冠结构的变化，为思茅松天然林的经营管理提供科学依据。 Abstract:Tree crown structure plays an important role in tree growth and forest management. Simao pine (Pinus kesiya var. langbianensis) is an important fast-growing coniferous tree and an important source of timber. Studying the crown structure of Simao pine natural forest has important theoretical and practical significance for forest management. Branch analysis of the crown structure of 34 sample trees was investigated in Simao District, Pu'er, Yunnan Province, China. The sample trees ranged in age (A) from 16 to 76 a, diameter at breast height (DBH) from 6.0 to 51.3 cm, tree height (H) from 6.3 to 27.4 m, crown width (CW) from 2.0 to 15.7 m, and crown length (CL) from 2.3 to 16.4 m. Models of the tree crown shape and structure variables were built by stepwise regression analysis using SAS statistical software. Three predictive models were established based on five independent variables of tree crown shape using a logarithmic linearization power function. Those variables were: the length of primary branches (BL), the diameter of primary branches (BD), the angle of primary branches (AB), the chord length of primary branches (BCL) and the crown radius (CR). Meanwhile, predictive models were established based on the three independent variables related to tree crown structure using three multivariate linear models: the growth height of primary branches (HGB), number of whorl branches (NWB) and the cumulative number of whorl branches (CNWB) models. Tests used to check the statistical accuracy of the models were carried out using independent samples. The total relative error (RS), mean relative error (EE), mean absolute relative error (RMA) and predictive accuracy (P) were selected to evaluate the models. The result showed that the eight predictive models performed well and the predictive accuracies of all models exceeded 91%; in particular, the accuracies of both the AB and HGB models were above 97%. Moreover, in the modeling of tree age (A), H and DBH resulted in different values in the different models. A did not have a significant effect on the crown shape variables in the models, but the crown structure variables did have a significant effect on A, indicating that the effect of age on the crown shape variables was not significant, but A did have a significant influence on crown structure variables. Furthermore, H did not have a significant effect on the models except for the modeled value of AB which did have a significant effect on the crown shape models; also, A had a significant effect on the modeling of crown structure. Meanwhile all modeled values for variables except for AB were significantly correlated with DBH, and all modeled values were positively correlated with DBH except for when the CNWB predictive model was used. This showed that when DBH was larger, BL, BD, BCL, CR were also larger, and more whorled branches were present. The negative correlation between DBH and stand density also showed that when stand density was higher, BL, BD, BCL, CR and NWB were all smaller. Overall, the models were suitable for describing the trends and inherent variability of the crown shape and the structure, and provided a valuable reference for the management of Simao pine natural forest. 参考文献 相似文献 引证文献

Initial effects of restoring natural forest structures in Estonia

The legacy of structural homogenization due to forest management for commercial products is a loss of biodiversity. A common policy in many European countries is to increase forest diversity by converting managed forests to more natural conditions. The aim of this study was to provide an early evaluation of the effectiveness of different restoration treatments to rehabilitate managed stands in order to increase their naturalness. Restoration treatments were imposed on 30–60years old conifer plantations including gap creation with and without added deadwood, added deadwood without gaps, gaps plus overburning, and controls. We sampled stand structure, understory vegetation and beetles before and after treatments on 50 circular permanent plots. Diversity of different groups responded differently to treatments with understory vegetation diversity increasing the most in gaps with burning, lichens in gaps without burning and bryophytes with the addition of dead wood. Increased beetle abundance and greater species diversity was a direct effect of changed light conditions inside the canopy. Gaps with overburning had the greatest recruitment of tree seedlings. Stands that were homogeneous pre-treatment increased in heterogeneity in structural conditions and microclimatic conditions after treatments and therefore richness and abundance of different species groups increased.

Structure and dynamics of temperate lowland natural forest in the Bialowieza National Park, Poland

The world-renowned Bialowiez·a National Park (BNP) in Poland has long been the object of research that provides information on the status and development of the entire, relatively large area of well-preserved lowland forest. For that reason, the aim of the work presented here was to characterize the current structure and dynamics of natural forests in Strict Reserve of BNP (SR-BNP), which covers 4584 ha. The research material encompassed the results of measurements on 460 temporary and 160 permanent sample plots. Results revealed an increase in the level of regeneration, whereas the standing volume is seen to have decreased slightly. Changes occurred in volume of certain tree species, as well as in proportions in given size classes they accounted for. The most marked increase was noted for Carpinus betulus, followed by Alnus glutinosa, Tilia cordata, Betula spp., Acer platanoides and Pinus sylvestris. Only in the case of Picea abies was a significant decrease noted. A decline of P. abies, mainly due to Ips typographus infestation, was revealed. Currently, only 6 of the 17 species of trees growing in the SR-BNP included specimens that were growing from the regeneration layer into the overstorey in more significant numbers. Due to a reduction of species diversity in ingrowth, a gradual depletion of species richness in the SR-BNP stands should be anticipated.

Landscape and microenvironmental conditions influence over regeneration dynamics in old-growth Nothofagus betuloides Southern Patagonian forests

Old-growth forests present a mosaic of different conditions resulting from the natural forest structure of the stands. Nothofagus betuloides forests have high spatial variability in regeneration without a clear correlation with overstory, and could be related to location of the stands in the landscape. The objective was to evaluate the influence of macro- and micro-variables over regeneration dynamics in old-growth N. betuloides forests, considering the effect of landscape (altitude and influence of the sea) and microenvironment conditions in the forest floor (closeness to trees, pits, understory cover type and bare soil). A total of four sites and 24 stands were sampled including forest structure, regeneration, understory cover and microclimate variables. Macro- (landscape) and micro- (microenvironment conditions in the forest floor) variables influenced over regeneration dynamics. Natural regeneration values (0.17 million ha−1 in the drier site vs. >4.52 million ha−1 in the other sites) not greatly depended on forest structure variables, but they were related to soil moisture (14% vs. 29–36% volumetric soil water content). Microenvironment conditions in the forest floor determined the recruitment as well as regeneration density, age and distribution of seedlings, whereas different soil moisture were related to each microenvironment type, generating positive (bare soil, ferns and mosses growing in turfs) or negative (mosses growing in mats, pits and proximity of the overstory trees) effects over regeneration, according to the soil moisture levels. These findings can be used to understand the functional integrity of the old-growth forest ecosystems and to propose silvicultural prescriptions to ensure regeneration recruitment and maximize growth potential in N. betuloides forests.

Spatio-temporal structure of natural forest: A structural index approach

The submitted paper deals with the analysis of stand structure of mixed species natural forest located in the Carpathians, Middle Europe. In order to evaluation of structural diversity we chose the combination of distance independent and nearest-neighbor indices. Following structural indices were calculated: Shanon-Weaver index (S-W), diameter differentiation index (Td), Gigi coefficient (G), mingling index (DMi) and Clark Evans index (CEd). The permanent research plot with area of 2.5ha was established in National Naure Reserve Hrončecký grúň and subdivided into 25×25m subplots. The combination of mentioned indices was calculated for each subplot separately. Regarding the diameter heterogeneity, the most part of analyzed structures showed the moderate level of tree size differentiation (S-W value 0.393±0.074). The presence of high number of juvenile individuals which already reached the diameter category “above 2cm” did not significantly affect the diameter variation of investigated stand. On the other hand, a massive establishment of subsequent generation led to creation of spatial structure characteristic by high level of vertical differentiation (Gini coefficient 0.47 in the structure characterized as the breakdown with successive generation). High climax species richness was confirmed by calculated values of DMi index (maximum relative presence in the category from 0.3 to 0.4). Each tree was surrounded by two and more different species individuals. Analysis discovers the negative developmental shift in the DMi values towards to less differentiated structures. Regarding the horizontal distribution the analysis of CEd values indicated that investigated natural forest can reveal a random distribution of individuals regardless of developmental stage.

ANALISIS KOMPOSISI DAN STRUKTUR VEGETASI TERHADAP UPAYA RESTORASI KAWASAN HUTAN TAMAN NASIONAL GUNUNG GEDE PANGRANGO

Gunung Gede Pangrango National Park (GGPNP) Forest Area has many ecosystem/forest vegetation type. The research aim was to analysis vegetation structure and composition at GGPNP forest area in many forest vegetation type. Research conducted by through vegetation analysis activity by used squared strip method. The results show that form of horizontal stand structure of Natural Forest stand tend to come near form of J-inversed (negative eksponensial) letter spread and form of horizontal stand structure graph of Mixed Rasamala Forest, Mixed Puspa Forest, Damar Forest, and Pine Forest stand be under horizontal stand structure graph of Natural Forest stand. Natural Forest has species number and species diversity index of higher level type at all levels growth of vegetation if compared to others forest vegetation types. Natural Forest has species evenness index of higher level type only at tree growth level, but rather lower at seedling growth level, sapling growth level, and pole growth level if compared to others forest vegetation types. There were 15 vegetation species found at all of forest vegetation types which have potency as pioneer vegetation in restoration activity of GGPNP forest area. Keywords: Vegetation structure and composition, forest restoration, national park

Structure and diversity of remnant natural evergreen broad-leaved forests at three sites affected by urbanization in Chongqing metropolis, Southwest China

Evergreen broad-leaved forests (EBLFs, lucidophyllous forests) are vegetation types characteristic of East Asia. The extent of EBLFs has decreased significantly due to long-term anthropogenic disturbance, and remnant EBLFs in urban area are rare and important landscape types contributing to biodiversity and sustainable development. This study focuses on remnant EBLFs on Mt. Gele (GL), Mt. Tieshanping (TSP), and Mt. Jinyun (JY), located from the inner city to outskirts of Chongqing metropolis, Southwest China. Species of Theaceae, Lauraceae, Symplocaceae, and other families, which are essential floristic components of primary EBLFs, were still the main components at the three sites. GL and JY showed higher biodiversity, with richer heliophytes and shade-tolerant species, respectively. Castanopsis carlesii var. spinulosa was the sole dominant species at all three sites in woody layer, with codomination by Pinus massoniana and Cinnamomum camphora at GL and by Machilus pingii and Castanopsis fargesii at JY; these evergreen broad-leaved trees all showed inverse-J or sporadic-shaped size distribution with large numbers of small stems, but the conifer tree Pinus massoniana showed unimodal distribution with small stems at GL. The height growth of tree species, especially Castanopsis carlesii var. spinulosa, was increasingly restricted from JY to TSP to GL. Sprouting is an important life history strategy at community and population level, and differences were exhibited from GL to TSP to JY. A rural–urban gradient from JY to TSP to GL was indicated in this study. Species composition, biodiversity, and stand structure of these remnant EBLFs showed obvious differences along this gradient, and conservation responses to address the effects of urbanization need to be carefully considered.

Stand Structure and Geographic Conditions of Natural Selection Forests in Central Hokkaido, Northern Japan(<Special Issue>Multipurpose Forest Management)

Stand Structure and Geographic Conditions of Natural Selection Forests in Central Hokkaido, Northern Japan(<Special Issue>Multipurpose Forest Management)

On the natural regeneration of dry heath forests in Finnish Lapland: a review of V. T. Aaltonen (1919)

This paper reviews the doctoral thesis of Viktor Toivo Aaltonen, published in 1919. The study was the first, and to this date the only detailed ecological description of the structure and regeneration of natural Pinus sylvestris-dominated dry heath forests in northern Finland. The average density of Pinus seedlings was 8766 ha–1. In general, Calluna sites had the most seedlings, followed by Cladina sites, postfire areas and Empetrum sites. Seedling abundance and quality declined with decreasing site fertility and increasing canopy cover. The main limiting factor for regeneration was regarded to be not canopy cover (shading), but its correlate, the intensity of below-ground competition. The mostly small understorey seedlings (10–30 cm) were considered to be unable to grow into the dominant tree layer unless a gap had formed in this layer. Several examples of the asymmetric competition between large trees and seedlings were provided. These included the distance-dependent adverse influence of isolated trees as well as gap and forest edge environments on seedling number and size. Special microhabitats, such as logs and their surroundings as well as uprooting spots, were found to be favourable regeneration sites. A special regeneration microsite effect was demonstrated by groups of seedlings around isolated large canopy trees, termed Tapio's gardens by local people. The study illustrates how the small-scale spatial heterogeneity observed in unmanaged dry pine forests influences tree population dynamics, leading to a wide range of variability in stand structures and successional stages. The value of Aaltonen's study perhaps especially lies in the description of a relatively intact ecosystem type, whose ecological quality has recently declined to the extent of becoming classified as a nationally threatened habitat type.

Stand structure and natural regeneration of degraded forestland in the northern mountainous region of Vietnam

Vietnam experienced significant alterations of forest environments during the last half of the twentieth century, and reforestation efforts have increased since the 1990s. This study developed comparisons of naturally regenerated and plantation forestlands in northern Vietnam in order to gain a better understanding of reforestation options for the dual objectives of biodiversity and commercial tree production. Stand structure of secondary natural forest after logging and shifting cultivation were investigated at two study sites (Hoa Binh Province and Phu Tho Province). Natural regeneration of seedlings between the secondary natural forests and nearby mixed species plantations were measured and compared. The dominant tree species consisted of Aporosa villosa, Ficus racemosa, Machilus bonii and Vernicia montan at the Hoa Binh site and Cinnamomum parthenoxylum, Ormosia balabsae and Lithocarpus gigantophyllus at the Phu Tho site, which are mostly pioneer species. The secondary natural forests had higher abundance and diversity indices of seedlings than the mixed species plantations. Soil fertility of the secondary natural forests was better than that of the mixed species plantations (P < 0.05). An important finding is that, for the study sites examined, secondary natural forest resulted in more diverse and better-stocked forests than plantation forestry, implying that in areas where reforestation is undertaken the silvicultural potential of natural regeneration should not be underestimated.

Saproxylic beetle assemblages in the Mediterranean region: Impact of forest management on richness and structure

Forests cover almost 30% of the Mediterranean region today, yet forest management activities have influenced structure and composition of both natural and planted forests. To date no study has been conducted to evaluate the impact of forest management on saproxylic beetle assemblages, although it is known that the Mediterranean is a biodiversity hotspot with a long-lasting human pressure on natural habitats. We provide an overview of saproxylic beetle assemblages of three forest types (mature Pinus halepensis forests, mature Pinus brutia forests, young Quercus calliprinos forests) in the East Mediterranean region using a one-year sample from 12 forest plots located in the north of Israel. The studied forest types differed in forest structure, but we found no significant difference in saproxylic beetle species richness. Aleppo pine forests showed the largest number of saproxylic beetle species. Forests dominated by P. brutia, a non-native tree species in Israel, show the lowest species number of all three forest types. Species composition differs substantially between oak and pine forests. A third of the species found either in P. halepensis or in Q. calliprinos forests being unique to these habitats, while a smaller proportion of unique beetle species is found in P. brutia forests. Several beetle species that were found both in oak and pine plots in our study develop exclusively on broadleaved shrubs or trees. This may be explained by the small distances between the studied pine trees and oaks in their proximity. Biodiversity in pine forests can be increased when these are mixed with broad-leaved trees, e.g. oaks in the understorey layer, as can be observed the natural regrowth in most of the planted pine stands in our research area. There is some evidence from other studies that older successional stages of oak forests are likely to host more species overall than the mature pine forests studied here. In order to enhance structural diversity foresters should allow for aging of single trees or stands, regardless of the tree species.

Invasion and management of alien Hedychium gardnerianum (kahili ginger, Zingiberaceae) alter plant species composition of a montane rainforest on the island of Hawai’i

Hedychium gardnerianum is a major invader of native Hawaiian forests and suspected of smothering native understory species and preventing native tree seedlings’ establishment. In this study, effects on species composition in six vegetation layers of a Hawaiian rainforest were examined (Tree Layer 1, Tree Layer 2, Fern-Shrub Layer, Herb Layer, Bryophyte–Herb Layer, and Bryophyte Layer). Three different area types were compared, which included (i) Natural area types with no influence of non-native species, (ii) Ginger area types with a Hedychium gardnerianum dominated herb layer, and (iii) Cleared area types, which were treated with herbicide to remove alien species in 1998. Species composition sampled in 2004 of the upper three vegetation layers (Tree Layer 1, Tree Layer 2, and Fern-Shrub Layer) differed little. The lower three vegetation layers (Herb Layer, Bryophyte–Herb Layer, and Bryophyte Layer) showed highly significant differences. Species composition in the Ginger area types showed notable abundances of non-native Psidium cattleianum, but low coverage of native species. In the area freed of Hedychium gardnerianum (Cleared area types), native species are regenerating, although it still reveals signs of disturbance. If this area is managed to prevent reinvasion, then it is likely to regain a natural forest structure.

Structure changes and succession dynamic of the natural secondary forest after severe fire interference

The structure and dynamic succession law of natural secondary forest after severe fire interference in recent 20 years were studied by adopting the method of deducing time series from the spatial sequence of vegetation in Heihe region, Heilongjiang, China. Two typical and widely distributed forest types in the study area, namely forest type A and forest type B, were selected as study subjects. Forest type A is pure broadleaf forest or broadleaf mixed forest mainly composing of superior Betula platyphylla and Populus davidiana in the area with gradient 25°. Species richness, vegetation coverage, important value, and similarity index of community in different layers (Herb, shrub, small tree, and arbor layers) were investigated and analyzed for the two typical forests. The results show that after fire interference, the species richness and coverage in each layer in forest type A were higher than that in forest type B. Both for forest type A and B, with elapse of post-fire years, the species richness and coverage of herbs and shrubs showed a decline tendency, while those of arbor layer present a rising tendency. Through comparison of the important values of species in each layer and analysis of community structure changes, the dynamic process of post-fire vegetation succession for forest type A and B was separately determined. Post-fire 80 years’ succession tendency of forest type A is B. platyphylla and Larix gmelinii mixed forest. Its shrub layer is mainly composed of Corylus heterophylla and Vaccinium uliginosum, and herb layer is dominated by Carex tristachya, Athyrium multidentatum, and Pyrola incarnate; whereas, the post-fire 80 years’ succession of forest type B is Q. mongolica and B. davurica mixed forest. Its shrub layer is mainly composed of lespedeza bicolar and corylus heterophylla and herb layer is dominated by Carex tristachya, Asparagus densiflorus, and Hemerocallis minor.

Community structure and biodiversity in plantations and natural forests of seabuckthorn in southern Ningxia, China

Two types of sampling plots of seabuckthorn (Hippophae rhamnoides) communities were investigated in Pengyang County of Ningxia region by a typical sampling method to study the characteristics of community structure and biodiversity. Composition and dominant species of each community were analyzed by the importance value of species as an index. The number of individuals and the importance value, as well as Sorensen’s similarity coefficient, Shannon-Wiener diversity index, Pielou’s evenness index and Simpson’s dominance index, were used as indices to compare characteristics of community structure, similarity and biodiversity between plantations and natural forests of seabuckthorn. The results indicate that the importance values of species of natural seabuckthorn communities were dispersed and the difference between dominant species was not statistically significant. Diversity indices of natural seabuckthorn communities reflected by species richness and evenness were higher than that of plantations. Community structure of natural seabuckthorn forests is more complex. We propose that natural forest can be used as sample to guide selection of plant species in silviculture in order to improve biodiversity of plantation.

The use of agricultural, open and forest habitats by juvenile Mauritius Kestrels Falco punctatus

Knowledge of tropical raptor habitat use is limited and yet a thorough understanding is vital when trying to conserve endangered species. We used a well studied, reintroduced population of the vulnerable Mauritius Kestrel Falco punctatus to investigate habitat preferences in a modified landscape. We constructed a high resolution digital habitat map and radiotracked 13 juvenile Kestrels to quantify habitat preferences. We distinguished seven habitat types in our study area and tracked Kestrels from 71 to 130 days old during which they dispersed from their natal territory and settled within a home‐range after reaching independence. Mean home‐range size was 0.95 km2 characterized by a bimodal pattern of intensity around the natal site and post‐independence home‐range. Compositional analysis showed that home‐ranges were located non‐randomly with respect to habitat but there was no evidence to suggest differential use of habitats within home‐ranges. Native and semi‐invaded forest and grassland were consistently preferred, whereas agriculture was used significantly less than other habitats. No difference was found between the available length of edge dividing native forest and grassland within a home‐range when compared to that available within a 2.35‐km buffer around their nest‐site, based on the maximum distance a juvenile was found to disperse. Repeating the analysis in three dimensions gave very similar results. Our results suggest that Mauritius Kestrels are not obligate forest dwellers as was once thought but can also exploit open habitats such as grassland. Kestrels may be using isolated mature trees within grassland as vantage points for hunting in the same way as they use the natural stratified forest structure. We suggest that the avoidance of agriculture is partly due to a lack of such vantage points. The conservation importance of forest degradation and agricultural encroachment is highlighted and comparisons with the habitat preferences of other tropical falcons are discussed.

Disturbance history and dynamics of an old-growth mixed species mountain forest in the Slovenian Alps

A long history of human presence in the Alps has made studies of natural forest structure, composition, and disturbance processes difficult. In the Slovenian Alps, we identified a mixed European beech ( Fagus sylvatica L.)-silver fir ( Abies alba Mill.)-Norway spruce ( Picea abies (L.) Karst.) stand with old-growth characteristics that escaped past cutting. We reconstructed the dynamics of the stand using a combination of stand and age structure analyses, dendroecological evidence of past canopy disturbance, and historical evidence of past human activities. The disturbance reconstruction revealed a stand-scale disturbance in the 1850s. Based on the presence of pit-and-mound topography throughout much of the stand and the absence of logging activities found in historical records, we assume this event was caused by strong winds. The current structure and composition of the stand are largely a result of this event. Post-disturbance forest development was dominated by the release of shade tolerant regeneration, especially F. sylvatica. The windthrow also created appropriate conditions (i.e. increased light and exposed mineral soil) for recruitment of less shade tolerant species, including larch ( Larix decidua Mill.) and maple ( Acer pseudoplatanus L.). The results suggest that periodic, intermediate severity wind disturbances, similar to the event documented here, may have had an important influence on pre-settlement forest dynamics in mixed mountain forests of the Alps, and add to the limited available information regarding the historic range of natural variability of disturbance processes. This information may be useful for forest management that attempts to emulate natural processes.

Long-Term Impacts of Fuelwood Extraction on a Tropical Montane Cloud Forest

Fuelwood extracted from natural forests serves as a principal energy source in rural regions of many tropical countries. Although fuelwood extraction (even low intensities) might strongly impact the structure and species composition of natural forests, long-term studies remain scarce. Here, we estimate the potential long-term impacts (over several hundred years) of such repeated harvesting of single trees on tropical montane cloud forest in central Veracruz, Mexico, by applying a process-based forest growth model. We simulate a wide range of possible harvesting scenarios differing in wood volume harvested and preferred tree species and sizes, and use a set of indicators to compare their impacts on forest size structure and community composition. Results showed that the overall impact on forest structure and community composition increased linearly with the amount of harvested wood volume. Even at low levels of harvesting, forest size structure became more homogeneous in the long term because large old trees disappeared from the forest, but these changes might take decades or even centuries. Although recruitment of harvested species benefited from harvesting, species composition shifted to tree species that are not used for fuelwood. Our results demonstrate that fuelwood extraction can have marked long-term impacts on tropical montane cloud forests. The results also offer the possibility to support the design of management strategies for the natural species-rich forests that achieve a balance between economic needs and ecological goals of the stakeholders.

Do restoration fellings in protected forests increase the risk of bark beetle damages in adjacent forests? A case study from Fennoscandian boreal forest

Gap fellings are used to promote multi-cohort structures and to restore other natural forest structures and processes in protected areas that have been altered by anthropogenic activities. Gaps and felled trees may also provide breeding material for species that in high numbers can cause significant tree mortality, growth reduction and consequent economic losses in surrounding production forests. In this study, the effect of restoration gap fellings on feeding intensity of Tomicus spp. (pine shoot beetles) was evaluated by counting fallen pine shoots at different distances from gaps in a protected area in eastern Finland. Gap fellings had a clear effect on the feeding intensity of the beetles. The average density of fallen shoots m −2 was 17 within a 10-m distance from gaps but decreased rapidly to around 4 at the distance of 50 m and beyond. The distance decay in shoot feeding is described well by the negative exponential models. Our results suggest that gap fellings have only a localized effect on shoot feeding by Tomicus in the forests surrounding the restoration gaps. In practical restoration, a buffer zone of 100–200 m around the gap fellings, as implemented here, is enough to minimize economically significant growth reduction in surrounding production forests. As shown in this study, restoration of natural forest structures and dynamics to protect biodiversity is not necessarily in conflict with forest hygiene objectives in production forests.

Fire Regime Attributes of Wildland Fires in Yosemite National Park, USA

Past attempts to suppress all fires in some western forests have altered historic fire regimes. Accumulated debris and dense understories of shade tolerant species coupled with a warmer climate have led to catastrophic wildfires. Prescribed fires and wildland fire use fires are used by land managers to reduce fuels and restore natural conditions. Little is known about how wildfires, prescribed fires, and wildland fire use fires differ in their fire regime attributes. We compared the attributes of start date, duration, 95th percentile burning index, size, fire rotation and fire return interval, and fire severity of 144 fires >40 ha that occurred in Yosemite National Park from 1974 through 2005, and mean patch size and patch squareness (an index of complexity) of 106 fires that occurred from 1984 through 2005. We used fire history, weather records, and the Relative differenced Normalized Burn Ratio (RdNBR) derived from satellite imagery to make the comparisons. Prescribed fires started both earlier and later than wildfires and wildland fire use fires, and had the shortest return intervals. Prescribed fires burned during periods with a lower 95th percentile burning index (an estimate of potential flame length and fire line intensity), and resulted in larger patches that were unchanged or that burned with low severity. Wildfires were the largest in size and had the largest percent area burned at moderate and high severity. Wildfires also had the largest moderate and high severity patches, and the high severity patches were the most square. The significant differences in fire regime attributes suggest that land managers seeking to restore natural fire regimes and forest composition and structure must consider more than the metrics of area burned or fuel loading.

Technological advances in temperate hardwood tree improvement including breeding and molecular marker applications

Hardwood forests and plantations are an impor- tant economic resource for the forest products industry worldwide and to the international trade of lumber and logs. Hardwood trees are also planted for ecological reasons, for example, wildlife habitat, native woodland restoration, and riparian buffers. The demand for quality hardwood from tree plantations will continue to rise as the worldwide consumption of forest products increases. Tree improve- ment of temperate hardwoods has lagged behind that of coniferous species and hardwoods of the genera Populus and Eucalyptus. The development of marker systems has become an almost necessary complement to the classical breeding and improvement of hardwood tree populations for superior growth, form, and timber characteristics. Molecular markers are especially valuable for determining the reproductive biology and population structure of natural forests and plantations, and the identity of genes affecting quantitative traits. Clonal reproduction of commercially important hardwood tree species provides improved plant- ing stock for use in progeny testing and production forestry. Development of in vitro and conventional vegetative propagation methods allows mass production of clones of mature, elite genotypes or genetically improved genotypes. Genetic modification of hardwood tree species could potentially produce trees with herbicide tolerance, disease and pest resistance, improved wood quality, and reproduc- tive manipulations for commercial plantations. This review concentrates on recent advances in conventional breeding and selection, molecular marker application, in vitro culture, and genetic transformation, and discusses the future challenges and opportunities for valuable temperate (or "fine") hardwood tree improvement.