Operational impacts to residual stands following ground-based skidding in Hyrcanian Forest, northern Iran

Hyrcanian （Caspian） Forest in northern Iran has a richness of biological diversity, with endemic and endangered species. The usage of ground-based skidding is well accepted practice for the extraction of timber from the forest, but this operation has tended to cause the greatest environmental problems. The aims of the study were to evaluate and comparison of operational impacts, residual stand damage, regeneration, and to quantify these effects such as： the extent of the damage, wounding patterns, size and distribution after logging operations that utilized two different methods： short log and long log. A Timbetjack cable skidder was used and the study location was in the Kheyrud Forest. Post harvesting assessment of damage to the residual stand was compared along skid trail by 100% inventory method and also for the assessment of regeneration damage along winching strips. The results show that along winching strips the percentage of damage to the regeneration was 44% and 36%, while the tree damages along skid trails reached 2.3% and 4.1% in the short log and long log methods, respectively. The greatest average amount of damage to a bole occurred along the first 1 m up from the ground （97%） and also within 4 m of the skidder centerline （80%）. These results show that the short log method causes less damage to the residual stand than the longog method. Tree location to skidder trail appears to have a significant effect on the number and height of scars on a tree. Well designed and constructed trails should be wide enough to allow wood extraction from the forest. Damage to the residual stand might be reduced by proper planning and training of logging crews.

Response of saproxylic insect communities to logging history, tree species, stage of decay, and wood posture in the central Nearctic boreal forest

Saproxylic insect assemblages are essential functional components of forest ecosystems that can be affected by forest management.We used a split-plot ANOVA design to analyze differences in selected saproxylic insects（all arthropod orders and dipteran and parasitic hymenopteran families） emerging from dead wood of sites with different logging histories（horse-logged,mechanically-logged and unlogged）,tree species（Populus and Picea）,stage of decay（early-and late-decay stages） and posture（standing and downed logs） in the boreal forest of central Canada.No clear effects of logging history were seen for the studied taxa; however,interaction between logging history and other dead wood features was apparent.Cecidomyiidae consistently emerged more from Populus than from Picea dead wood.Most of the studied saproxylic families were more abundant in late-decay than in early-decay wood.Dipterans of the Cecidomyiidae,Ceratopogonidae,Empididae,Mycetophilidae and Sciaridae families,and hymenopterans of the Diapriidae and Ichneumonidae families were significantly more abundant in downed than in standing dead wood.In contrast,Mymaridae was most abundant in standing dead wood.Our study provides evidence that some insects at high taxonomic levels respond differently to dead wood quality,and this could inform future management strategies in the boreal forest for the conservation of saproxylic fauna and their ecological functions.

Chaotic Genetic Algorithm-Based Forest Harvest Adjustment

Forest harvesting adjustment is a decision-making,large and complex system. In this paper,we analysis the shortcomings of the traditional harvest adjustment problems,and establish the model of multi-target harvest adjustment. As intelligent optimization,chaotic genetic algorithm has the parallel mechanism and the inherent global optimization characteristics which are suitable for multi-objective planning the settlement of the issue,specially in complex occasions where there are many objective functions and optimize variables. In order to solve the problem of forest harvesting adjustment,this paper introduces a genetic algorithm to the Forest Farm of Qiujia Liancheng Longyan for forest harvesting adjustment firstly. And the experimental result shows that the method is feasible and effective,and it can provide satisfactory solution for policy makers.

Forecasting the development of boreal paludified forests in response to climate change: a case study using Ontario ecosite classification

Background：Successional paludification,a dynamic process that leads to the formation of peatlands,is influenced by climatic factors and site features such as surficial deposits and soil texture.In boreal regions,projected climate change and corresponding modifications in natural fire regimes are expected to influence the paludification process and forest development.The objective of this study was to forecast the development of boreal paludified forests in northeastern North America in relation to climate change and modifications in the natural fire regime for the period 2011–2100.Methods：A paludification index was built using static（e.g.surficial deposits and soil texture）and dynamic（e.g.moisture regime and soil organic layer thickness）stand scale factors available from forest maps.The index considered the effects of three temperature increase scenarios（i.e.＋1°C,＋3°C and＋6°C）and progressively decreasing fire cycle（from 300 years for 2011–2041,to 200 years for 2071–2100）on peat accumulation rate and soil organic layer（SOL）thickness at the stand level,and paludification at the landscape level.Results：Our index show that in the context where in the absence of fire the landscape continues to paludify,the negative effect of climate change on peat accumulation resulted in little modification to SOL thickness at the stand level,and no change in the paludification level of the study area between 2011 and 2100.However,including decreasing fire cycle to the index resulted in declines in paludified area.Overall,the index predicts a slight to moderate decrease in the area covered by paludified forests in 2100,with slower rates of paludification.Conclusions：Slower paludification rates imply greater forest productivity and a greater potential for forest harvest,but also a gradual loss of open paludified stands,which could impact the carbon balance in paludified landscapes.Nonetheless,as the thick Sphagnum layer typical of paludified forests may protect soil organic layer from drought and deep burns,a significant proportion of the territory has high potential to remain a carbon sink.

CHARACTERISTICS OF SMALL RODENT COMMUNITY IN DIFFERENT AGED CUT-OVER AREAS IN DAILING MOUNTAIN

The field investigation of small rodent community was made in Liangshui Reserve, Heilongiiang Province, in 1992. Species composition and percentage of each species of the small rodents in different aged clear-cut-over areas were analyzed. The change of rodent community was associated with the change of vegetation cover. Forest harvest, which results in change of light, temperature, water and othcr ecological factors, made change of vegetation cover and was the main cause for the change of small rodent community. The small rodents were low in number of species population and diversity index in the inatial stages after clear cutting. The diversity index of rodents in order of different aged cut-over areas were 5-year-old area >20-year-old area > 28-year-old area > 1 -year-old area > 10-year-old area.