Arboreal lichen in uncut and partially cut subalpine fir stands in woodland caribou habitat, northern Idaho and southeastern British Columbia

To better understand the effects of partial cutting on arboreal lichen production within woodland caribou (Rangifer tarandus caribou) habitat, lichen was hand picked from 1228 branches on 307 subalpine fir (Abies lasiocarpa) trees in Idaho (ID), and in British Columbia (BC). Lichen biomass from partially cut stands was compared with biomass on trees from adjacent uncut stands at each site. Arboreal lichen biomass did not differ significantly between uncut and partially cut stands. Total number of branches per tree did not differ significantly between uncut and partially cut stands. Live branches had more lichen than dead branches. Species composition of arboreal lichen changed in partially cut stands compared with adjacent uncut stands. The ratio of live to dead branches was substantially different within the BC partial cut.     

Cavity and bark nesting bird response to partial cutting in Northern conifer forests

We investigated whether partial cutting used to mimic small-scale natural disturbances could maintain cavity and bark nesting breeding birds. We assessed changes in the relative abundance of cavity nesting birds in two intensities of partial cutting, compared to uncut and clearcut stands, 9 years post-treatment. We then examined the relationship between forest structure and nesting abundance (stand scale) and compared characteristics of used nest and forage trees to unused trees (tree scale). The relative abundance of most species was highest in either heavy removal or light removal treatments 9 years post-harvest. Brown creepers were most abundant in uncut, and red-breasted sapsuckers were most abundant in clearcut and heavy removal treatments. The proportion of deciduous trees and the density of dead trees were the best predictors of nest abundance. Individual nest tree use was predicted by the presence of large deciduous trees with broken tops and early to advanced stages of decay. Forage tree use was predicted by the presence of large conifer trees in advanced stages of decay. To maintain breeding habitat for cavity nesters, we suggest that forest managers retain the specific structural attributes required for nesting, but also the diverse forest conditions required for foraging.     

Comparison of Forest Biomass Across a Human-Induced Disturbance Gradient in Nepal's Schima-CastanopsisForests

Abstract

This paper presents estimations of aboveground tree biomass (combined for boles and branches) in Nepal's Schima-Castanopsisdominated warm-temperate forests. The biomass estimations are presented for five forest stands purposively sampled in a larger study to represent different harvesting intensities. Two categories of biomass estimates are provided: (1) for living trees that are standing, and (2) for cut trees that have been removed. Biomass of standing trees were estimated by using diameter at breast height (dbh) and total height measurements as predictor variables in appropriate regression models. Biomass of cut trees were estimated in two steps: measurements of stump diameters and heights were used first to predict dbh and total heights of cut trees; these values were then regressed to obtain biomass estimates for the missing trees. Data were gathered from 2,361 live trees and 2,962 stumps in 170 sample plots across the five forest stands. Estimates of mean standing-alive biomass ranged from a minimum of 16 ton/ha in the severely disturbed forest to a maximum of 479 ton/ha in a relatively undisturbed (reference) forest. Estimates of mean cut biomass ranged from a minimum of 24 ton/ha in a second reference forest to a maximum of 183 ton/ha in the severely disturbed forest. The biomass estimates in the relatively-undisturbed, reference forests are well above the 95% upper confidence interval of the global mean. Similar findings of high productivity have been reported for temperate forests of the Central Himalaya in India and Eastern Himalaya in Sik-kim. The findings of this study in the Nepalese Central Himalaya support the conclusion that productivity potential is high in the temperate Himalayan forests. The study's findings and methodology should be useful for preliminary development of guidelines in the region to regulate forest biomass growth, yield, and harvest.     

The effects of partial cutting on stand structure and growth of western hemlock–Sitka spruce stands in southeast Alaska

The effects of partial cutting on species composition, new and residual-tree cohorts, tree size distribution, and tree growth was evaluated on 73 plots in 18 stands throughout southeast Alaska. These partially cut stands were harvested 12–96 years ago, when 16–96% of the former stand basal area was removed.Partial cutting maintained stand structures similar to uncut old-growth stands, and the cutting had no significant effects on tree species composition. The establishment of new-tree cohorts was positively related to the proportion of basal-area cut. The current stand basal area, tree species composition, and stand growth were significantly related to trees left after harvest (p<0.001). Trees that were 20–80 cm dbh at the time of cutting had the greatest tree-diameter and basal-area growth and contributed the most to stand growth. Diameter growth of Sitka spruce and western hemlock was similar, and the proportion of stand basal-area growth between species was consistent for different cutting intensities.Concerns about changing tree species composition, lack of spruce regeneration, and greatly reduced stand growth and vigor with partial cuts were largely unsubstantiated. Silvicultural systems based on partial cutting can provide rapidly growing trees for timber production while maintaining complex stand structures with mixtures of spruce and hemlock trees similar to old-growth stands.     

兴安落叶松过伐林枯立木分布格局特征分析

以内蒙古根河林业局潮查林场境内的在20世纪80年代初主伐利用后形成的兴安落叶松过伐林为研究对象,利用兴安落叶松林8块标准地每木定位数据,分析林木分布格局和样方(5 m×5 m)林木株数对枯立木株数影响,探讨了林分大树和更新幼树位置与枯立木位置的关系,阐明了枯立木分布格局形成机制。结果表明:1)各树种枯立木比例,随树种组成成数增加而增大。枯立木主要在更新幼树阶段形成,径级分布集中在4径阶以下,其株数占总数的比例平均达82.2%。在更新幼树(含枯立木)中,生成枯立木的比例平均达8.8%。2)枯立木分布格局为聚集分布。林木分布格局、样方林木株数和更新株数与枯立木株数有显著正相关关系,林木分布格局对枯立木分布格局无显著影响。林木聚集度越大,形成枯立木的可能性越大,数量也就越多。3)枯立木位置与更新幼树和大树位置有显著相关关系。主要表现为落叶松和白桦相互关系。枯立木出现位置主要在大树和更新幼树集聚区域。大树对枯立木形成影响较更新幼树大,而且均以落叶松较白桦明显。白桦更新幼树对落叶松枯立木的形成,无显著影响。受影响的枯立木主要是枯立木株数中所占比例和树种组成成数较高的树种。影响枯立木位置的林木主要取决于其样方内位置和林木株数。     

Cutting and resprouting of Detarium microcarpum and herbaceous forage availability in a semiarid environment in Burkina Faso

The tree-shrub savanna ‘Forêt Classée de Nazinon’ (Burkina Faso) is submitted to a management of grazing and rotational cutting of Detarium microcarpum. This species resprouts after cutting. In order to investigate whether this silvopastoral land use system is sustainable, aboveground herbaceous biomass was measured on subplots under uncut trees (‘uncut’), next to the stubs of cut trees (‘cut’) and on subplots not influenced by the (former) crowns of trees (‘open grassland’) in four lots. These lots were cut one, three, six and seven years before the study. Vegetation composition of the lots and the composition of the diet of cattle were also determined. Comparisons were made between treatments and lots. Herbaceous biomass was lower in the open grassland subplots than in uncut or cut subplots. We speculate that soil enrichment and more efficient precipitation input in (former) tree crown zones could have resulted in this pattern. Cutting and subsequent resprouting of trees did not lead to significant differences in herbaceous biomass between cut and uncut subplots. The most simple explanation for this is that the trees could extend their roots beyond the location of their neighbouring trees. Biomass and coverage of perennial grasses, mainly Andropogon ascinodis and Andropogon gayanus, did not change in lots cut one, three or six years before the study, but decreased dramatically in lots that were cut seven years before the study. When foraging, cattle spent more than 90% of their time feeding on these species. This indicates that, as a consequence of tree cutting, forage availability may be reduced to the point where local herdsmen are forced to take their cattle to another region. This revised version was published online in August 2006 with corrections to the Cover Date.     

Stand structure of an uneven-aged fir–beech forest with an irregular diameter structure: modeling the development of the Belevine forest, Croatia

This study focuses on the problem of irregular diameter structure in a silver fir–beech selection (plenter) forest with a “surplus” of large diameter trees and a lack of natural regeneration and small diameter trees. We sampled 274 plots (900 m² each) in the Belevine research site (266.24 ha) in the mountain region Gorski Kotar (Croatia), where diameter (dbh) distribution, diameter increment, and natural regeneration were analyzed in detail. A low density of natural regeneration, weak annual recruitment of small (10 cm dbh) diameter trees (only five trees per hectare), delayed diameter growth of trees, and a low annual rate of trees reaching the next dbh class were attributed to the current irregular dbh structure. The stand development prediction for the next 50 years is based on a simulation model, which considers the current diameter structure, increment, recruitment, and future cutting regime. Intensive cutting in the first of five 10-year cutting cycles (intensity higher of 25%) is needed to initiate natural regeneration and to accelerate growth of young silver fir trees. In the next 50 years, the irregular diameter structure will be gradually improved.     

Saproxylic beetles in high stumps and residual downed wood on clear-cuts and in forest edges

Abstract

This study evaluates how the placement and the different possible outcomes of a spruce retention tree affected species richness and assemblages of spruce-associated saproxylic beetles. In a field experiment in the boreal zone of central Norway, high stumps were created and compared with residual wood pieces (i.e. top boles with branches), in clear-cuts versus in forest edges. Flight interception traps were mounted close to the substrate. The results were analysed using rarefaction techniques, ordination (DCA) and anova. It was found that the placement of retention trees of spruce does matter: beetle assemblages were significantly different in stumps in the four treatments. For all species pooled, the species richness was higher in stumps in clear-cuts than in stumps or boles in the forest edge. Four red-listed species were more abundant near stumps than boles, and two red-listed species were more abundant in clear-cuts than forest edge. To cater for the variety of habitat preferences among forest beetles in managed forest, managers should leave both standing spruce trees (many of which will end up as windthrown, downed boles) and some high stumps (to secure some upright dead wood), in both exposed clear-cut and semi-shaded forest edge.     

红花尔基沙地樟子松天然林枯立木特征分析

[目的]了解沙地樟子松天然纯林中枯立木的数量及空间结构特征,探究枯立木形成的原因,为樟子松林的保护和经营提供依据。[方法]在沙地樟子松天然纯林中设置2块1 hm~2的大样地,用全站仪对样地中所有胸径大于5 cm的立木进行定位并进行全面调查;对调查样地的基本特征,枯立木的数量特征及径级分布进行了分析,提出了用于表达林分中枯立木微环境的活立木比的概念,并采用林分空间结构参数一元分布和二元分布分析方法,对枯立木与其最近4株相邻木的关系进行分析。[结果]2块不同密度的樟子松天然纯林下更新幼苗和枯立木数量相差较大,密度较小(样地1)的样地更新幼苗和枯立木较少,而密度较大的样地(样地2)中枯立木达到200棵,林下更新幼苗数量达到15 280株·hm~(-2);樟子松天然纯林样地内枯立木主要以小径级木为主,胸径集中在11 cm以下;样地1枯立木径级连续分布,幅度较窄;样地2中的枯立木径级幅度较宽,但在20 22 cm缺刻,有2株大于23 cm的枯立木;2块样地中枯立木的分布格局均为随机分布,样地1中枯立木周围的4株相邻立木大多为活立木,且胸径较枯立木大;样地2中,只有一半的枯立木周围的最近4株立木为活立木,且有三分之一以上的枯立木胸径不是最小的,枯立木有连续分布的现象。2块样地中枯立木的角尺度-大小比数二元分布特征的差异不明显,而角尺度-活立木比二元分布特征和大小比数-活立木比二元分布特征差异明显,样地1中枯立木的最近4株随机分布于其周围的相邻木为活立木且胸径大于枯立木的比例明显高于样地2,而枯立木最近4株随机分布于其周围的相邻木有枯立木的比例明显小于样地2。[结论]樟子松天然纯林枯立木以小径级林木为主,枯立木的数量与林分密度相关,林木竞争是林木死亡的主要原因,密度过大也会产生病虫害,因此,对天然樟子松纯林要进行适度经营,保持合理密度。     

Do aggregated harvests with structural retention conserve the cavity web of old upland forest in the boreal plains?

Boreal species that are dependent on old forests, such as many cavity-using birds and mammals, are at high risk from conventional harvest practices. These species may benefit from ecologically sustainable forest management practices that increase heterogeneity within stands and across landscapes. Structural retention within cutblocks and spatial aggregation of cutblocks into large (1000s ha) harvest units are two such management practices being implemented by forestry companies in the boreal plains of Alberta and Saskatchewan. However, little is known about the implications of these practices for old forest species. The goal of our study was to determine if the cavity-using assemblage associated with old upland forest in this region is retained within aggregated harvests with structural retention. We used a cavity web approach to describe and contrast interactions among cavity excavators (woodpeckers, chickadees, and nuthatches) and the secondary (i.e. non-excavating) species reusing their cavities. We described the cavity web for two intact landscapes of old upland forest and for two aggregated harvest landscapes. We identified four key excavators of intact forest: yellow-bellied sapsucker (Sphyrapicus varius), hairy woodpecker (Picoides villosus), northern flicker (Colaptes auratus), and pileated woodpecker (Dryocopus pileatus). These woodpeckers should be considered key excavators primarily of mature and old aspen forest, which dominated the study landscapes. Each woodpecker filled a unique role in the cavity web and all are important for conservation of two mammal and three bird species that used their cavities. In the short term (i.e. within four years post-harvest), the key cavity excavators and many secondary cavity-using species associated with intact forest were retained in the harvested landscapes. One secondary species (American kestrel (Falco sparverius)) was unique in the harvest cavity web. Compared to the intact cavity web, the harvest web had lower abundance of sapsuckers, greater abundance of flickers, and high reuse of flicker cavities by kestrels. These differences were associated with the shift from intact forest to a landscape characterized by patches of old forest surrounded by early-successional habitat. Abundances of hairy and pileated woodpeckers were too low to detect differences between intact and harvested landscapes. The key excavators primarily used trembling aspen (Populus tremuloides) for cavity trees and thus aspen should be targeted for retention in harvested landscapes. A more detailed examination of the habitat requirements of the key excavators is needed to develop best practices for tree and patch retention and ensure conservation of the cavity-using assemblage in aggregated harvests.     

Long-term re-use of tree roosts by European forest bats

The few studies that have assessed the long-term patterns of re-use of tree cavities by bats all concern North American bats. We studied long-term re-use of tree cavities by two species of European bat, Daubenton's bats (Myotis daubentonii) and noctules (Nyctalus noctula). Cavities were inspected during consecutive years via direct capture of bats (more than 340 positive capture events, ca 2950 captured bats), observations of emerging bats, or by listening for bats during the early evening when bats emit typical vocalization (over 160 positive checks, over 450 observed bats). Between 1968 and 2007, we found 80 tree cavities used by bats (mostly excavated by woodpeckers) in the Czech Republic. Although more than half of the cavities were occupied for ≤4 summers, 28 cavities (35%) were re-used for 5–10 years. The longest period a cavity was used was 11 and 16 years for Daubenton's and noctule bats, respectively. Sixteen tree cavities (20%) were occupied solely by Daubenton's bats and 33 cavities (41%) were occupied only by noctules. The other 31 cavities (39%) were used by both species, either at separate times or simultaneously. Our data suggest that the larger volume of a cavity, the longer duration of re-use and the greater the probability of being occupied by both species. Continuous excavation of cavities by woodpeckers prevented the overgrowth of old cavities by calluses, which keep cavities accessible to bats. We suggest that woodpeckers may be the most important providers of suitable roosts for forest bats in Central Europe. Roosts were found in both economically valuable trees (Quercus robur and Tilia cordata) and less valuable tree species (Salix fragilis and Alnus glutinuosa). Economically valuable trees in our study area were long-lived and likely provide roosting habitat for longer periods but matured at a greater age. However, less economically valuable trees reached maturity and started to decay in a relatively short time, which may provide suitable cavities at a younger age. Maintaining both types of trees within forests may help provide suitable roosting oportunities for tree-dwelling bats in the Czech Republic.     

Long-term growth analyses of Japanese cedar trees in a plantation: neighborhood competition and persistence of initial growth deviations

The individual growth of tree diameter at breast height (dbh) is analyzed in an even-aged plantation of Cryptomeria japonica from stand age of 45 to 94 years, to examine how the growth of individual trees has been affected by the changes in spacing resulting from thinning operations. At any age, a significant proportion (0.37–0.46) of the variation in dbh growth during a 5–11-year period was explained by dbh at the beginning of the period, probably due to greater leaf mass of larger trees. Next, either one-sided or two-sided competition was added to the model, by calculating the basal area (BA) of neighboring trees around each tree within a given radius or BA for trees having larger dbh than the focal tree within the radius. After preliminary analyses, a radius of 8 m was selected as the critical range for tree competition. Although both types of competition explained a significant proportion (0.09–0.43) of growth variation, one-sided competition was not significant at ages greater than 54 years. Based on the model at 45 years of age, the initial deviation of growth rate for each tree from the predicted rate was calculated and added to the models as a third variable. This raised the coefficient of determination up to 0.50–0.74. These findings have practical significance for forest plantation management, particularly for controlling the growth of standing trees via thinning, to produce high-quality timber in the future.     

Interactions among cutting frequency, reserve carbohydrates, and post-cutting biomass production in Gliricidia sepium and Leucaena leucocephala

The ability of trees and shrubs to coppice vigorously after being cut or pruned is of great importance in the management of agroforestry systems. In a study conducted in the seasonally dry climate of Ibadan, Nigeria, frequent cutting progressively decreased concentrations of starch and total reserve carbohydrates in Gliricidia sepium (Jacq.) Walp. and Leucaena leucocephala (Lam.) De Wit. In frequently cut trees, starch was severely reduced in the stumps of both species. In contrast, soluble sugar concentrations in roots and stems of both species were consistently maintained at or above the levels in uncut control trees, suggesting that sugar levels were maintained through the hydrolysis of starch reserves. No starch replenishment occurred during the six weeks after cutting. In trees that were cut and then allowed to grow undisturbed during the wet season, replenishment of stem starch began within three months after cutting. Shoot regrowth after cutting decreased starch levels first in stems and, only after additional cuts, in roots. Dry-season cuts had little effect on reserve carbohydrates in G. sepium but quickly reduced stem starch in L. leucocephala. Frequent cutting decreased dry matter production, and this decrease was correlated with reduced levels of reserve carbohydrates.This revised version was published online in November 2005 with corrections to the Cover Date.     

Comparison of tree size structure and growth for partially harvested and even-aged hemlock-spruce stands in southeast Alaska

The effects of partial cutting on tree size structure and stand growth were evaluated in 52 plots in 13 stands in southeast Alaska that were partially harvested 53–96 years ago and compared with 50-year-old even-aged stands that developed after clearcutting. The net basal-area growth was greater in the partially cut plots than in the uncut plots, and basal-area growth generally increased with increasing cutting intensity. However, the basal-area growth of all of the partially harvested stands was significantly less than the growth of 50-year-old even-aged stands, and net basal area growth over the 50 year period since partial harvesting was about 33–43% of the growth of the even-aged stands. Partial cutting maintained stand structures similar to uncut old-growth stands, and the cutting had no significant effect on tree species composition. The tree size distribution of the partially harvested stands was far more complex and well distributed in comparison with the 50-year-old even-aged stands, and included the presence of several trees with diameters of more than 100 cm. These trees included both large-diameter spruce and hemlock trees and were a distinctive structural feature that was noticeably lacking in the even-aged stands.     

Density effects on the conifer mortality in declining spruce-fir forest in northern Japan: Implication of bark beetle attack to, cause spruce decline

We examined mortality patterns of two conifer species in relation to tree abundance and species composition in a declining spruce-fir forest in Akan National park, Hokkaido, northern Japan. The data taken from eleven 58 m × 58 m square study plots showed that percentage basal area (BA) of dead trees of canopy trees during the last decade was 49% forPicea jezoensis (Sieb. et Zucc.) Carr and 30% forAbies sachalinensis (Fr. Schm.) Masters. InP. jezoensis, percentage basal area (BA) of dead trees was positively related to both BA of its own species and proportion of it to BA of all species, whereas it was not significantly related to both of these variables inA. sachalinensis. Multiple logistic regression with dbh as a confounding factor also indicated that, inP. jezoensis, the proportion of dead stems was positively affected by the stem density of conspecific trees, whereas it was negatively affected by the stem density of the other species in each study plot. However, inA. sachalinensis, the proportion of dead stems was significantly related to neither of these factors. The different mortality pattern between two conifer species suggests that the spruce bark beetle,Ips typographus (L.), which is a serious pest of spruce, may have caused theP. jezoensis decline. Instead of wind-throw or thinning that usually initiate this bark beetle attack, some unknown factors seemed to predispose the trees to insect attack. These unknown factors may also explain the high mortality ofA. sachalinensis in this forest. This research was supported by FFPRI Project, Ministry of Agriculture, Forestry and Fishery.     

Floristic diversity and carbon stocks in the periphery of Deng–Deng National Park,Eastern Cameroon

Carbon is continuously being removed from the atmosphere by photosynthesis and stored in carbon pools(live,dead,and soil carbon)of forest ecosystems.However,carbon stock in dead wood and of trees with diameters at breast height(dbh)between 5 and 10 cm is often not considered in many studies carried out in the Congo Basin Forest.The relationship between tree diversity,life-forms and carbon stocks has received little attention.This study was carried out on the outskirts of Deng Deng National Park(DDNP)to determine tree diversity(dominant families,species richness and Shannon index),assess carbon stocks in the five carbon compartments(living tree,understory,fine roots,dead wood and litter)as well as to analyze the relationship between(1)carbon stocks and tree diversity;and,(2)between carbon stock and life-forms.The Shannon index of trees≥10 cm dbh ranged from 2.6 in riparian forest to 4.3 in secondary forest;and for the tree between 5 and 10 cm,it ranged to 1.56 in riparian forest to 3.68 in the secondary forest.The study site housed 16 species,7 genera and 3 families which are only found in trees of dbh between 5 and 10 cm.The average total carbon stock of the five compartments varied from 200.1 t ha-1 in forest residues to 439.1 t ha-1 in secondary forest.Dead wood carbon stock varied from 1.2 t ha-1 in riparian forests to 12.51t ha-1 in agroforests.The above ground carbon stocks for trees with diameter between 5 and 10 cm varied from 0.7 t ha-1 in young fallow fields to 5.02 t ha-1 in old secondary forests.This study reveals a low but positive correlation between species richness and total carbon stocks,as well as a significant positive relationship between life-forms and total carbon stocks.The findings highlight the need for more data concerning carbon content of dead wood,carbon of trees≥5 cm<10 cm dbh and the relationship between carbon stocks and tree diversity from other areas of the Congo Basin for a good understanding of the contribution of tropical forests to climate change mitigation.     

Long-term response of planted conifers, natural regeneration, and vegetation to harvesting, scalping, and weeding on a boreal mixedwood site

This study reports 14th-year response of a boreal mixedwood stand to different harvest intensities (uncut, 50% partial cut with and without removal of residuals after 3 years, and clearcut), spot site preparation treatments (none and scalped), and chemical weeding frequencies (none, single, and multiple) in northeastern Ontario. The response variables include the survival and growth of planted white spruce (Picea glauca [Moench] Voss) and jack pine (Pinus banksiana Lamb.), height and density of natural regeneration and shrubs, and cover of shrubs and non-woody vegetation. Harvesting and weeding generally improved survival and growth of planted trees, although white spruce survival did not significantly differ among the three weeding frequencies. Harvesting tended to increase heights of hardwood (mostly trembling aspen (Populus tremuloides Michx.)) and conifer (largely balsam fir (Abies balsamea (L.) Mill.).) natural regeneration, cover and density of shrubs, and cover of herbs, lichens, and ferns. Chemical weeding reduced height, density and cover of shrubs, height and density of hardwood regeneration, and fern cover, but increased moss and lichen cover. Spot scalping did not significantly affect planted seedling, natural regeneration, or the vegetation.Maximum survival and growth of planted white spruce and jack pine were achieved using a combination of clearcutting and multiple weeding. However, partial cutting followed by a single weeding produced acceptable survival and reasonable growth of planted trees, particularly for white spruce. Partial canopy removal alone substantially reduced the amount of hardwood regeneration, relative to clearcutting, but did not adequately suppress understory shrubs. Significant improvement in seedling growth following multiple weedings was evident primarily in the complete canopy removal treatments: 50% partial cut with removal of residuals after 3 years and clearcut. While the effects of harvesting and weeding on planted crop trees found in the 5th-year assessments generally persisted at year 14, survival decreased, likely due to light competition from developing hardwood and shrubs.     

Effect of cutting height and cutting interval on dry matter yield of Leucaena leucocephala (Lam) De Wit

The effect of cutting height and cutting interval on dry matter production of Leucaena leucocephala (Lam) De Wit was investigated at Njala, Sierra Leone using three year old Leucaena trees. Four cutting heights, (25, 50, 75 and 100 cm), and two cutting intervals (one and three months), were adopted.Dry matter yields were highest at the 75 and 100 cm cutting heights, especially at the longer, three-monthly, cutting interval. They were significantly reduced by more frequent cutting, probably due to the increased number of recovery phases.Leaf nitrogen yields per tree for trees cut at three-monthly intervals were over twice as high as the total yields obtained from monthly cutting over the same period.     

The effects of selective logging on stand structure and the regeneration of subboreal forests in Hokkaido, northern Japan

We investigated the effects of selective logging on stand structure and regeneration in selectively logged subboreal forests in Taisetsuzan National Park in Hokkaido in northern Japan. The basal area decreased and the size structure of trees altered in the stands studied due to repeated, intense selective logging, in which larger trees were cut down as a priority. Sapling density in the stands was much lower than that in primary forests. In the simple and multiple regression analyses that were used to estimate the effects of selective logging on sapling density, sapling density had a significant positive correlation with tree density and had little correlation with the density of logged stumps or the height ofSasa (dwarf bamboo) growing on the forest floor. These results suggest that the establishment sites around canopy trees influenced the establishment of saplings, rather than the gaps caused by selective logging. However, both the coefficient of determination and the standardized partial regression coefficient of multiple regression analysis were higher for the stand with a dense cover ofSasa than for the stand with a sparse cover ofSasa. Thus, the success of regenerating forests with selective logging depends on both the site of advanced regeneration and the light conditions that regulate growth.     

Phytosociological characteristics and diversity of trees in a comanaged protected area of Bangladesh: Implications for conservation

ABSTRACT

The Chunati Wildlife Sanctuary (CWS), a degraded protected area in southeastern Bangladesh, had been under comanagement since 2004. This study examined phytosociological characteristics and diversity of trees in CWS and discussed villagers’ opinions on the impact of comanagement on forest conservation. Following a stratified and systematic sampling 140 circular plots, 17.84-m radius each, were laid out in seven forest beats for the assessment of phytosociological characteristics and tree diversity. Several key-informant interviews and 15 focus group discussions were held to explore the impact of comanagement on forest conservation and on villagers’ livelihood. A total of 93 tree species were identified having a diameter at breast height (dbh) of ≥ 5 cm in 36 plant families. The dominant species were Acacia auriculiformis, Dipterocarpus turbinatus, Ficus hispida, and Tectona grandis. The average density of trees was 239 trees/ha of which 60% was composed of planted exotic species. Nearly 90% trees were belonging to 5- to 15-cm dbh class and the Shannon-Wiener index was 3.15. The comanagement governance had brought positive changes in forest conservation. However, to sustain the engagement of poor villagers in the comanagement and conservation of degraded CWS, more collective efforts are needed to support their living.