Impacts of forest management on liana diversity and community structure in a tropical forest in Ghana: implications for conservation

We studied the impacts of liana cutting as a forest management tool on liana diversity(species richness,Shannon diversity index) and community structure(diameter distribution, basal area, species dominance) in the Asenanyo Forest Reserve, Ghana. Two types of silviculturally treated forests were studied: Logging treated(LT)and Tropical Shelterwood System(TSS) treated forests. An untreated primary forest was included as a control, resulting in three forest management systems. Lianas with diameter C2 cm were identified in ten 40 9 40 m2 plots within each management system. Liana cutting significantly reduced liana species richness, Shannon diversity index, and basal area in the LT forest after two decades.However, liana species richness and basal area werecomparable in the TSS treated and untreated forests, indicating significant recovery in the former after over six decades. S?rensen similarity index of liana species composition between the untreated forest and each of the treated forests was moderate. Our findings suggest that liana cutting most likely influenced the dominance of some liana species. In view of the adverse impact of blanket liana cutting on liana diversity, selective liana cutting is recommended as a means of controlling liana numbers while maintaining liana diversity.     

Genetic diversity in natural populations of Gmelina arborea: implications for breeding and conservation

Gmelina arborea is a valuable plantation tree species that is native to South and Southeast Asia. In this study, 534 samples representing 19 natural populations in India, China, Thailand and Myanmar were analyzed with 10 polymorphic microsatellite markers. The genetic diversity analysis revealed highly polymorphic loci (N_a?=?16.4), a good level of genetic diversity (H_o?=?0.56; H_e?=?0.83) and the deficiency of heterozygotes in G. arborea populations evidenced by positive fixation index and deviation from Hardy?CWeinberg Equilibrium in all loci and most populations. The Analysis of Molecular Variance attributed 21, 10 and 69% of total genetic diversity to among-region, among-population (within region) and within-population variation. Unweighted Pair Group Method with Arithmetic Mean dendrogram and Principle Coordinate Analysis revealed three separate clusters composed of China, India and Thailand/Myanmar that were consistent with geographical distance and the presence of natural barriers to gene flow. Populations from within India grouped together genetically consistent with geographical locations, with the exception of the Nowgong population (eastern India), that might have originated from the Kasa area (western India) with which it has high genetic similarity. Understanding genetic diversity and structure of G. arborea populations serve as an important reference for tree breeding programs and conservation strategy. Breeding populations of G. arborea should include selections from each of the major geographic regions to maximize genetic diversity and heterosis. Vegetative propagated clones of elite trees can be used for plantation to address the issue of high level of segregation among seed derived plants.     

Patterns in aboveground carbon allocation and tree architecture that favor stem growth in young Scots pine from high latitudes

The production and allocation of aboveground biomass and the characteristics of tree architecture were examined in eight-year-old Scots pine (Pinus sylvestris L.). Considerable among-tree variation existed in tree architecture, total aboveground dry mass production, and dry mass partitioning among tree parts. A linear relationship existed between needle and branch mass. Stem mass was directly proportional to tree height, which in turn was directly proportional to the allocation ratio between stem mass and total needle + branch mass production. The architectural characteristics that were related to a high proportional allocation to stem and high stemwood production were a large mean shoot volume, large mean number of branches per whorl, long needle retention and a high crown length/crown width ratio. Individual trees were found that combined high stemwood production with both high harvest index and high stemwood specific gravity.     

The Internal Transfer of Nutrients in a Scots Pine Stand 2. The Patterns of Transfer and the Effects of Nitrogen Availability

The fall of fine litter was 4.5 tonnes ha^–1 y^–1,(78% needles) returning to the ground 36.6 kg N, 2.2 kg P, 7.6kg K, 12.1 kg Ca and 2.0 kg Mg. Nutrient input in rainfall (880mm in 1978) was 2.6 kg N, 0.4 kg P, 4.3 kg K, 7.6 kg Ca and1.4 kg Mg. Throughfall was 534 mm. The method of Miller, Cooperand Miller (1976) was used to estimate aerosol contributions,leaching and absorption. Retranslocation estimates were 59.6kg N ha^–1 y^–1 (55% of Requirement), 8.5 kg P (64%R), 42.0 kg K (56% R) and 1.2 kg Mg (14% R). Retranslocationwas unchanged, but uptake increased with added N % P and decreasedwith added sawdust and glucose. Other typical effects of nutrientamendment were observed: with added N % P growth increased,current tissues had higher concentrations of N and P and litterfalldecreased in the first year but was heavier in the second year:with added sawdust and glucose, growth declined but concentrationsof N and P remained substantially the same.     

Biogeography of mangrove and saltmarsh vegetation: implications for conservation and management in Australia

Despite an undeserved reputation for being dull and homogenous systems, mangal and saltmarsh in Australia have highly complex patterns and processes. Their role as key edge systems between land and sea has implications for many species which have larval stages in mangal and saltmarsh, but spend adult life as benthic, pelagic or demersal species. Many such species are also important commercially. Mangal and saltmarsh are both highly dynamic systems, reacting rapidly to changes in hydrological condition and sedimentation. In many areas of the world mangal and saltmarsh are threatened systems, especially near human habitation. Appropriate management strategies for mangal and saltmarsh are therefore critical for both conservation and sustainable use, the two key objectives of the Convention on Biological Diversity. Clearing and associated development, invasion of alien species, pollution effects and poor management are the key threats to these systems. Management at a bioregional level, including the development of a comprehensive system of protected areas, is identified as the key management strategy which will ensure an adequate future for these dynamic systems.     

Floristic diversity and composition of the Biteyu forest in the Gurage mountain chain (Ethiopia): implications for forest conservation

The Afromontane forests of Ethiopia have been under a serious degradation threat. Assessment of floristic diversity and species composition in Biteyu forest of Gurage mountain chain in the central Ethiopia was conducted to examine the pattern of forest structure. Thirty plots of 30 m×30 m were used to record the vegetation and environmental data using systematic sampling technique. The local name, plant scientific names, DBH, height,species abundance and percentage canopy cover of plant species were recorded. Shannon diversity index and Sorensen's coefficients was used for comparison among communities and similar forests in the country. Threats to the forest biodiversity in Biteyu were determined by counting cattle interference and wood stumps as disturbance indicators. Relative Euclidean Distance measures by using Ward's method(linkage) was applied for cluster analysis. Environmental variables were also recorded in each plot. Woody species population structure, basal area and importance value index were analyzed using spreadsheet programs. Data on species distribution and environmental variables in the forest were analyzed by canonical correspondence analysis. A total of 190 species in 154 genera under 73 families were identified. Twenty species were found to be endemic taxa to the Flora Area. Only three plant community types were identified from the cluster analysis due to the high human influence. The Sorensen's coefficient showed the resemblance of the Biteyu forest with other Dry Evergreen Afromontane forests in the country. Moreover, altitude and slope strongly affect the species composition and structure of Biteyu forest. Given the high anthropogenic influence, high endemism, high dependence of the local community on the forest resources, forest conservation and restoration measures should be done by stakeholders.     

Genetic variation of Taxus baccata L. populations in the Eastern Alps and its implications for conservation management

Abstract

The English yew (Taxus baccata L.) is an endangered rare tree species in Austria. More than 600 bud samples were collected from seven populations in three regions of the Eastern Alpine mountains for estimating their genetic structures by using isozyme gene markers. Nine gene loci encoding for seven enzyme systems were investigated. The revealed 32 alleles indicate a higher multiplicity of the east alpine gene pool compared with other European regions. English yew showed a high level of genetic variation, with a mean number of alleles per locus (A/L) of 2.7. A total of 76.4% of the loci were polymorphic, the average expected heterozygosity was (H _e) 0.274 and the mean observed heterozygosity (H _o) was 0.238. The relative proportion of genetic differentiation among the regions was found to be 6.2%, the level of gene flow was high (Nm=3.78) and the level of inbreeding (0.130) among the regions was medium. The obligatory out crossing (dioecious plant), the long generation time, the ability to regenerate from stump and the seed dispersal by birds and rodents might contribute to the high level of genetic variation found within the population. The conservation propositions are discussed with respect to the genetic structure and the poor recruitment of this species.     

Oak regeneration using the shelterwood-burn technique: management options and implications for songbird conservation in the southeastern United States

Shelterwood silviculture is commonly used to regenerate oaks in upland stands. However, competition from other species such as tulip-poplar (Liriodendron tulipifera) may deter oak regeneration when these traditional shelterwood techniques are used. The shelterwood-burn technique is a relatively new tool for regenerating oak-dominated stands on some upland sites while simultaneously minimizing undesirable hardwood intrusion with prescribed fire. Once successful oak regeneration has been achieved, three options are available which will result in different vegetative structure and composition within a stand and subsequently different habitats for songbirds. These options are: complete or partial canopy retention, post-harvest prescribed burning and complete canopy removal. Canopy retention, burning and removal treatments will create, respectively, two-age stands that are likely to harbor a diverse mixture of mature forest and early successional species; park-like woodlands with open woodland species; or early-successional habitats with shrubland species. We suggest that shelterwood-burn systems and the management options associated with them offer viable alternatives for managing both songbird and timber resources where oak-dominated stands are the desired goal in upland southeastern sites.     

Genetic diversity and population structure analysis of Pistacia species revealed by phenylalanine ammonia-lyase gene markers and implications for conservation

Information on population genetic structure and crop genetic diversity is important for genetically improving crop species and conserving threatened species.The PAL gene sequence is part of a multigene family that can be utilized to design DNA marker systems for genetic diversity and population structure investigation.In the current study, genetic diversity and population structure of100 accessions of wild Pistacia species were investigated with 78 PAL markers.A protocol for using PAL sequences as DNA markers was developed.A total of 313 PAL loci were recognized, showing 100% polymorphism for PAL markers.The PAL markers produced relatively more observed and effective alleles in Pistacia falcata and Pistacia atlantica, with a higher Shannon's information index and expected heterozygosity in P.atlantica, Pistacia vera and Pistacia mutica.Pairwise assessment of Nei's genetic distance and genetic identity between populations revealed a close association between geographically isolated populations of Pistacia khinjuk and Pistacia chinensis.The accessions of wild Pistacia species had more genetic relationship among studied groups of species.Analysis of molecular variance indicated 19% amongpopulation variation and 81% within-population variation for the PAL gene based DNA marker.Population structure analysis based on PAL revealed four groups with high genetic admixture among populations.The results establish PAL markers as a functional DNA marker system and provide important genetic information about accessions from wild populations of Pistacia species.     

Contribution of participatory forest management towards conservation and rehabilitation of dry Afromontane forests and its implications for carbon management in the tropical Southeastern Highlands of Ethiopia

Participatory forest management (PFM) has been applied as an approach to create a framework for collaborative forest management between local communities and government forestry agencies. This study was designed to assess the contribution of PFM approach in improving forest status in the Southeastern Highlands of Ethiopia. Landsat satellite imageries of four years were used to evaluate the trends and rate of deforestation before and after PFM interventions. Socio-economic data were collected from sample household surveys, key participants, focus group discussions, and field observations. The results showed that there was high rate of deforestation before PFM intervention as forestland has decreased by 19% (2531 ha) between 1990 and 2000. However, after the PFM intervention (2000–2016), the forest cover has increased by 247 ha (2.2%). During this period, net 1016 ha of shrub-lands were converted into forestland owing to significant forest regeneration. In addition, most sampled households (94% and 96% from lower and upper altitudes, respectively) perceived that PFM had significantly contributed to improve forest regeneration in their locality. This study revealed that PFM can serve as a stepping stone for carbon financing mechanisms to reduce greenhouses emission and enhance carbon sinks via forest resources.     

Secondary edge effects in regenerating forest landscapes: vegetation and microclimate patterns and their implications for management and conservation

Forest regrowth is expected to gradually mitigate edge effects in forest landscapes fragmented by timber harvest, but our understanding of edge effect persistence and dynamics over time is still incomplete. Our main objective was to take a critical look at the role of forest regrowth in mitigating the initial edge effects on microclimate and understory vegetation in northern hardwood forests of the eastern United States. We compared canopy closure, hourly air temperature, soil moisture, and understory vegetation at increasing distances from forest edges (0, 5, 10, 20, and 30 m) along twelve transects placed across new and older forest edges (3–4 or 16–19 years old) created by forest harvest. Open, new forest edges exhibited pronounced edge effects on microclimate and shade-intolerant plants, but these were almost completely moderated by forest regrowth on the cleared side of older edges where dense young forest developed with a new canopy comparable in cover to adjacent mature forest. There were no initial edge effects on shade-tolerant vegetation across new forest edges, but the shade-tolerant vegetation declined in mature forest near old forest edges adjacent to dense young forest that supported only sparse understory vegetation. These delayed secondary edge effects of young dense forests on adjacent mature forests have not been previously documented and they should be more explicitly included in forest management considerations. We suggest an integrated system for managing and mitigating both the immediate primary and delayed secondary edge effects in those working forest landscapes where biodiversity conservation is of high priority.     

青岛耐冬山茶的多样性特征及其保护

青岛近海岛屿分布的山茶是典型的亚热带区系成分,因为其耐寒性强被当地人称为“耐冬”。通过研究耐冬山茶种群的形态和基因多样性特征,以及栽培种群与野生种群之间的遗传分化和机制,对耐冬山茶种群的濒危原因和保护策略进行了分析和探讨,认为必须有效保护一定大小的野生种群及其生境,才能从根本上保持“耐冬”种群的多样性资源。     

Tree Mortality,Foliage Recovery and Top-kill in Stands of Scots Pine (Pinus sylvestris) Subsequent to Defoliation by the Pine Looper (Bupalus piniaria)

In 1996, the pine looper (Bupalus piniaria) (L.) defoliated 7000 ha of Scots pine (Pinus sylvestris L.) forest at Hökensås, in southern Sweden. To study tree mortality, foliage recovery and top-kill, plots were laid out in stands with varying levels of defoliation in autumn 1997. Tree mortality peaked 2 yrs after defoliation, and amounted to 25% in stands suffering from 90–100% defoliation. Suppressed trees suffered higher mortality than intermediate and dominant trees. In stands suffering <90% defoliation, tree mortality did not exceed 8%. Foliage recovery in moderately and severely defoliated stands was not complete at the end of the 4 yr study period, whereas slightly defoliated stands had regained full foliage in 1998. Top-kill was most frequent in severely defoliated stands, and 50% of all trees in these stands suffered from top-kill at the end of the study period in spring 2001.     

浅谈园林绿地管护成本的构成及控制

对邯郸市2001～2006年园林绿地养护费用进行了认真分析,指出绿地养护管理的费用主要由人工费、水费、燃料费、车辆费、电费、农药费及其他费用构成,提出通过政府加大对园林绿地养护管理资金的投入、降低自来水用量、放开养护管理作业市场、充分发挥绿地自我调节功能以及抓好园林绿地养护质量标准和经费定额的落实等,便可极大地做好绿地养护管理的成本控制。     

Exploratory analysis of structural diversity indicators at stand level in three Italian beech sites and implications for sustainable forest management

The present study introduces an exploratory data analysis based on structural indicators with the aim to assess the effect of silvicultural practices on tree stand structure. The study was carried out in three Italian beech forests of different ages with stand structures that originated from dissimilar regeneration and cultivation techniques(Cansiglio, northern Italy, Chiarano, central Italy,and Mongiana, southern Italy). Ten structural indicators were considered when investigating the latent multivariate relationship between stand structure attributes before and after thinning operations by using a multiway factor analysis(MFA). The MFA results identified the older stand at Cansiglio as more homogeneous for cultivation regimes,and more stable to practices when compared with the younger sites(Chiarano and Mongiana). Heterogeneous stands were sensitive to silvicultural practice thus suggesting their possible impact on forest attributes. The proposed approach proved to be an operational tool to evaluate comprehensively the response of forest structure to planned interventions.     

Recovery of floristic diversity,composition and structure of regrowth forests on fallow lands: implications for conservation and restoration of degraded forest lands in Laos

New Forests - In Laos, there are extensive shifting cultivation areas and regrowth forests spontaneously established on fallow lands. The aims of the study were to conduct a comparative study of...     

Genetic diversity and structure of Drimys brasiliensis in southern Brazil:insights for conservation

Population genetics studies are widely recognized for generating useful knowledge for biodiversity conservation.To date,however,little is known about the levels and distribution of genetic diversity of Drymis brasiliensis(Miers LC),a tree species from the Atlantic Rainforest.Therefore,in this study,we investigated how genetic diversity is distributed within and among populations of D.brasiliensis from southern Brazil using allozyme markers to genotype reproductive trees(8 populations) and seedlings(3 populations).Furthermore,in two populations,we established two permanent plots(5.1 and 1 ha) to analyze fine-scale genetic structure(FSGS).Studied populations presented low levels of genetic diversity(reproductive=0.085;seedlings=0.054) and high fixation indexes(reproductive=0.396;seedlings=0.231).Genetic divergence among populations was equal to 0.05,which is significant,signaling that few populations can conserve large portions of the species total genetic diversity.FSGS was only detected for one population,when reproductive individuals were separated by less than40 m.Low genetic diversity combined with high fixation indexes clearly signal a risk of losing diversity.Therefore,conservation efforts should be aimed at enhancing gene flow within the studied populations.