Average Number Of Trees Research Articles

Structural properties of pure and mixed bosnian pine stands on Mt. Zeletin

The subject of this research are stands of bosnian pine in the area of the mountain massif Visitor with Zeletin in Montenegro. Considering the fact that these forests are unexplored, due to their small area and the absence of economic interest (the strictest protection regime), the research task of this paper is to conduct an adequate research of one of the most preserved white-bark pine populations in this areas in structural and partly production terms. The bosnian pine stands on Mt. Zeletin belong to two management units: FMU ?Pisevska Reka - Zeletin? and FMU ?Kutska Reka? which occupy an area of 160 ha. The research included the accessible parts of sections 2/b, 3/a, 5/a, 28/a and 28/s, in which 8 sample plots (SP) of an 30 ar area each were established (4 SP in pure and 4 SP in mixed stands). The SPs are vertically distributed between 1,550 and 1,850 m a.s.l. In pure stands, the average number of trees (for 4 SPs) is 723 pcs?ha-1, the basal area is 74 m2?ha-1, and the volume is 529 m3?ha-1, which are considered high values given the conditions in which these stands have developed. In mixed stands, the numerical elements show significantly higher values: the number of trees is 875 pcs?ha-1, the basal area is 87 m2?ha-1 and the volume is 721 m3?ha-1. A high degree of correlation was found between the values of volumes (unweighted and weighted) and the values of dominant heights. The mixed stands reveal a more heterogeneous structural development. Bosnian pine trees cluster at short distances, which is probably the result of a struggle for survival in highly unfavorable conditions. As these stands are subjected to spontaneous development over a long period of time, their research provides the opportunity to get to know more about bosnian pine ecology. Considering its modest requirements towards habitat conditions, bosnian pine has considerable advantages when choosing a species for afforestation of the most unfavorable sites.

조경수의 생산 관리를 위한 식재 수종 및 규모의 시계열 분석 - 수도권 민간건설 아파트 단지를 중심으로 -

This study was conducted to understand the change time-series of landscape trees planted in apartment complexes and to predict the demand for pine trees among landscape trees. From 2003 to 2020, the average number of trees used in apartment complexes in the Seoul metropolitan area were 51, and various types of trees were used in the late 2010s compared to the mid-to-late 2000s. The average planting quantity was 149,567trees/1 complex, and the time series change was not noticeable. Comparing evergreen trees and deciduous trees, there was a difference between the planted species and the planted quantity. Compared to evergreen trees, deciduous trees were planted with relatively diverse species. Evergreen trees were planted in large quantities, with fewer varieties than deciduous trees. The types of trees and shrubs consist of a ratio of 6:4, and shrubs accounted for 97.6% of the total planting volume. Compared to the amount of planting, the varieties of trees planted are not diverse. When analyzing the planting status of pine trees with high preference and use value of landscaping trees, the planting volume tends to increase, and in particular, the planting ratio of large pine trees is increasing. Predicting the demand for pine tree planting in apartment complexes will continue to increase the amount of planting, especially with special trees with a root diameter of 40 cm or more. In response to these changes in demand for landscaping trees, a strategy is required to discover and produce various plant materials. In particular, since the demand for large pine trees is continuously expected to increase, production management should be carried out so that pine trees with the shape and specifications required by the market can be supplied.

Potential of Wood Harvesting Residues and Residual Stand Damage due to Timber Harvesting: A Case Study at PT Austral Byna in Central Kalimantan, Indonesia

The practice of timber harvesting in natural forests which has been conducted up to now still leaves wood harvesting residue and residual stand damage. Most condition of wood harvesting residue is still good and can be utilized. The objective of this research was to determine the potency of wood harvesting residue and residual stand damage on timber harvesting in natural forests. The data on wood utilization, wood harvesting residue, and residual damage were collected from three sample plots. The sample plots were arranged in a systematic and purposive manner, and the data were processed with tabulation and average analysis. Research results showed that the average volume of wood being utilized was 9.212 m3 tree−1. The average volume of wood harvesting residues was 2.310 m3 tree−1, and the total average volume of wood harvesting residues which were good, defected, and broken was 2.121 m3 (80.952%), with an average volume for good wood harvesting residue condition of 1.038 m3 (34.808%). Proportions of wood harvesting residues were 2.154 m3 (94.444%) consisting of buttress as large as 0.102 m3 (5.159%), stumps as large as 0.375 m3 tree−1 (23.597%), butt as large as 0.855 m3 (35.930%), and end part as large as 0.821 m3 (29.758%). The average number of trees with a diameter of 20 cm which were damaged due to felling and skidding was 5 trees ha−1 (5.40%) and 6 trees ha−1 (6.58%), respectively.

دراسة اقتصادية لأثر الحيازة الفدانية على الکفاءة الإنتاجية والاقتصادية لمحصول الزيتون فى محافظة شمال سيناء

Despite the importance of the olive crop in North Sinai Governorate, this crop is characterized by its low production efficiency in light of the high age of some of its trees, and the presence of local varieties characterized by low productivity, and the main problem of research is limited to the decrease in the cultivated area of ​​the olive harvest from about 52.8 thousand feddans in 2013, To about 35.5 thousand feddans in 2017, a decrease of about 32.8%. The research aims in general to study the effect of feddan holding on the productive and economic efficiency of olive farms in North Sinai Governorate, where the research used the descriptive analysis method to present the topics included in the research, in addition to the quantitative analysis method using some standard models such as multiple regression in its double logarithmic form. In estimating production functions, and in cubic forms in estimating cost functions, The study also relied mainly on primary data through a stratified random sample of 70 farms It is estimated that the fruitful area of ​​the olive harvest increases annually by a statistically significant amount of about 2.6 thousand feddans, which represents about 9% of the annual average, and on the productive indicators of the research sample farms, the average number of trees per acre is about 56 trees, and the general average productivity of the tree is about 81 kg / year, and the general average productivity per feddan was about 4.6 tons / year. The general average age of olive trees in the research sample was about 28.3 years. The general average of the holder's share was about 3.9 feddans It is also evident that the relative importance of the rent item is high among the fixed costs items, as well as the rented labor item, and organic fertilizer is among the variable costs items. It is evident that the first holding category farms (less than 3 feddans) achieved the highest rates of lost income, while the third holding category farms The lowest rates of lost income, which confirms the need for intensification and rationalization of the elements of production within this category. Regarding the profit margins, the results indicated that the general average of the net yield from the olive harvest amounted to about 14.4 thousand pounds, which is equivalent to about 3.1 pounds per kilogram of the crop. The general average of the return over the variable costs of the olive harvest was about 19.1 thousand pounds, which is equivalent to about 4.2 Pounds per kilogram of crop. The general average of the added value was about 17.9 thousand pounds With regard to economic efficiency, the results indicated that every pound spent on fixed and variable production costs achieves an added value of about 1.36 pounds. It was found that the farms of the third holding category for the olive harvest were superior to their counterpart in the first and second categories in profit margins, as well as indicators of economic efficiency. This indicates the importance of expanding olive cultivation to take advantage of the capacity savings in the short and long term.

Green Infrastructure Implementation Programmes at National Level: Case Study “National Project – Support of Biodiversity with Green Infrastructure Elements in Municipalities of Slovakia”

Abstract EU-wide strategy promotes the deployment of green infrastructure across Europe. Integrating green infrastructure in spatial planning, policy and strategy development at regional/national levels is the task of each EU member state. The aim of this article is to give an example and evaluate one of the ongoing projects at national level, namely National project – Support of Biodiversity with Green Infrastructure Elements in Municipalities of Slovakia “Green municipalities of Slovakia“. The aim of the national project is to implement green infrastructure at local level through vegetation elements in order to maintain and restore biodiversity and ecosystems outside of protected areas Natura 2000. The programme supporting tree planting in rural municipalities is an important tool for the creation of basic elements of green infrastructure throughout Slovakia. As part of the national program, an implementation plan for 6 municipalities in Slovakia in 2020 is proposed. Subsequently, the implementation projects in terms of the use of vegetation in different categories of green spaces, types of vegetation, representation of tree species, including costs and benefits, are proposed. Based on the results, the potential and limits of the programme and specific suggestions for its further use are set. In 6 municipalities, a total of 17 suitable localities were selected for the project, which is an average of 2.83 localities per municipality. A total of 467 woody plants individuals were proposed, representing a total of 19 woody plants species. The total cost of planting is an average of €12,601.10 per municipality, €7,312.05 per ha of area, and €161.90 per single tree. The average number of trees per ha is 45.15 individuals and per each municipality it is 77.83 trees. In the conclusions, a potential risk of the programme regarding the subsequent maintenance of trees, which is not funded under the program, is highlighted.

Possibilities of Utilizing Oil Palm (Elaeis guieneensis) Trunk as a Solutionfor Sustainable Agricultural Waste Management

Oil Palm covers nearly 9600 hectares of Sri Lanka. The replacement process occurs once for 25-30 years creates nearly 200 tons of agricultural waste per hectare. The normal procedure of uprooting un- economical plantations is by using bachore machine. Conventional methods of clearing oil palm trunks after remaining materials in the field cause problems such as increasing breeding places for pests like rhinoceros beetles and rats increase the disease incidents in immature plants, hindering field operations and taking long time to decompose remains. Therefore, sustainable utilization of oil palm trunk bio mass is important. Oil palm trunks from Elpitiya plantation were used for the experiment. A trunk has an average biomass of 1550kg with an 8m mean length. The average number of trees per hectare is 125 per one replacement cycle. Bark is removed from trunks and cut into pieces and chopped by using an electrical chopper. The chopped pulp (initial pulp) was grinded by mortar and pestle and blender separately to produce pulp 1 and pulp 2 respectively. Molasse produced using pulp 1 and pulp 2, give final brix values of 58 and 54.4 respectively. Vinegar was produced using pulp1 and pulp 2 shows an undesirable light brown suspension with an alcohol percentage of 2%. Pots and planting containers for nurseries prepared from initial pulp can be used for nurseries and effective in direct field planting. The study revealed there is a possibility of preparing molasse and planting containers from oil palm trunks. Vinegar production process needed to be further studied.

Dendrochronology and climate in the Brazilian Atlantic Forest: Which species, where and how

As dendrochronology noticeably increased in tropical regions during the last three decades, some general patterns could emerge from comprehensive analyses of case studies. Here, we investigated the state of dendrochronology’s contributions to the bioclimatology of wood species in the Brazilian Atlantic Forest (AF). We asked: Which species and sites had cross-datable growth-ring series suitable for bioclimatic inference? What were the sampling and analytical methods applied? What do these studies tell us about plant-growth sensitivity to climate conditions? Which knowledge gaps may be identified? For this, we searched for articles addressing climate-growth relationships by means of cross-dated growth-ring chronologies within the AF. We found 11 articles, covering 16 chronologies from 10 species. The average number of trees in chronologies was 16 individuals. 87% of chronologies suggested a positive precipitation signal, and some positive temperature signal was identified in all chronologies that were compared to monthly or seasonal temperature series. The findings are supported by the specialized literature, which points out the influence of precipitation in the tropics. However, making stronger conclusions about the role of climate on the growth of AF tree species will require greater efforts in surveying the diverse tree flora and developing rigorous cross-dated chronologies. Keywords: climate-growth relationship, dendrochronological parameters, tropical forest, subtropical forest.

A quantitative study of pollarding process in silvopastoral systems of Northern Zagros, Iran

Aim of study: This research attempts to quantitatively describe the pollarding process in the northern Zagros, western Iran.Material and methods: An inventory of all trees was conducted in three representative stands in the pollarded section (DBH ≥ 5 cm): DBH, total height, trunk height and crown diameters were measured. At the time of pollarding, 10% of the foliage stacks were randomly selected and weighed. The positions of each store tree (i.e. special trees capable of enduring the weight of a certain number of leafy branches (average 600 kg)) and horizontal distance of pollarded trees associated with each store tree was recorded.Main results: The number and weight of foliage stacks resulting from pollarding of each tree correlated (0.48 and 0.43, respectively) with their crown diameter. The average dry weight of leaf biomass was 1,525.6 ±108.1 kg/ha and there was a significant difference between the selected stands. The average pollarded area and the average number of trees in the pollarded area of each store tree was 501.1±210.4 m2 and 9.4±3.5 trees, respectively.Research highlights: The number of pollarded trees associated with each store tree and the weight of stored foliage stacks on them are determined by the distance between pollarded trees and store trees, the number of trees around the store trees and the ability of selected store trees to bear the weight of foliage stacks.

SURVEI POTENSI GAHARU DENGAN SISTEM AGROFORESTRI DI KECAMATAN XIII KOTO KAMPAR, KABUPATEN KAMPAR (STUDI KASUS: DESA PULAU GADANG DAN DESA KOTO MASJID)

This study aims to determine the potential of gaharu with agroforestry system in the village of Pulau Gadang and Koto Masjid Village. The research was conducted in Desa Gadang Village and Koto Masjid Village. The data collected is then analyzed descriptively. Based on the results of reseach conducted by gaharu plant species is Aquilaria malaccensis with the potential of the plant in the village of Pulau Gadang which is 7 years old as 70 trees, 8 years 920 stems and 9 years as many as 440 stems. Meanwhile, Koto Masjid Village is at the age of planting 7 years as many as 100 stems, 8 years as many as 300 stems and 9 years as many as 400 stems. The potential of gaharu plants in the community of Pulau Gadang Village with an average land area of ​​1.09 Ha / farmer, the average number of gaharu-producing trees is 84.12 trees / farmers, and the average tree / Ha is 78.03 trees / Ha / farmers. While in Koto Masjid village with average land area is 1.2 Ha / farmer, average number of tree 145,45 trees / farmer, and average tree / Ha counted 68,67 tree / Ha / farmer. 
 

Modeling human population patterns on tree density

In order to evaluate the possible correlation between the tree density and the human population density, the forested area in Nav Asalem districtlocated in Guilan Province was selected. The descriptors of tree number and basal area per hectare as well as the stand density index were used to determine the tree density, which was conducted from a 2014 forest inventory including 62 cluster (558 plots) systematically scattered over 30 % of the forest area. In addition, to determine the density of the human population, circular buffers at intervals of 1 to 7 km from the center of each cluster was considered and population density of each layer was calculated using buffering functions. Statistical results showed that the average basal area, average number of trees and the average stand density index was 23.16 m 2 /ha, 243 per ha and 178.25 respectively and also different human population density in each buffer. Using Pearson correlation test indicated a significant negative correlation between the stand density index and basal area (DBH >15 cm) with human population density. There was no significant relationship between the number of trees per hectare and the human population density except at 7 km. This findings support studies regarding the disturbance has strong correlative with the number of residents per unit area at up to 7 km from clusters and greater control on anthropogenic interventions should be the main priority of sustainable forestry in Hyrcanian forests of northern Iran. Due to the existence of an effective relationship between the components of the tree density and human population in the forest, policy-makers and planners of natural resources could benefit management patterns appropriate to above components to achieve sustainable management.

Tree regeneration in patch cutting in Norway spruce stands in northern Finland

ABSTRACTThe study focused on the success of regeneration on patch cuts in spruce-dominated stands in terms of stocking and tree height. It was based on an experiment in the Kainuu region in northern Finland. The experimental design included 8 stands with 58 clearcut patches of variable size (0.09–0.37 ha), on which either natural regeneration without site preparation or site preparation and planting of Scots pine was applied. A regeneration survey was conducted 13–15 growing seasons after treatments. Patches without site preparation had been restocked quite well from natural seed sources. The average number of trees was about 11,000 ha−1, of which 1700 ha−1 crop trees. With site preparation and planting, the stocking levels were also very high, 25,000 and 2100 ha−1, respectively. One hundred percent of the planted patches and 75% of the naturally regenerated patches had an acceptable density. Restocking was equally good across the range of patch sizes. Tree growth had been somewhat slower in the smallest patches than in the largest ones in the range. Natural regeneration was capable of yielding good regeneration results in most patches, especially when site preparation was applied. Stocking levels and height development were higher yet in the planted patches.

THE PEAR INDUSTRY IN THE REPUBLIC OF CROATIA

Pear (Pyrus communis L.) is a popular fruit species in Croatia. It is grown mainly on small family farms and less on large plantations. By growing areas, compared to other fruit species, pear is in 9th place, with a share of 3.31% (860 ha out of 26,003 ha). Since the production is less than 10,000 t per year significant quantities of fruit for consumption and processing have to be imported. Based on 15-year data the most common rootstock is Pyrus communis L. (39.1%), followed by Quince BA 29 (25.4%), MC (17.8%), MA (16.4%), Sydo (0.7%) and Adams (0.5%). The most common cultivars is ‘Williams’ (27.3%), followed by ‘Conference’ (16%), ‘Bella di Giugno’ (8.5%), ‘Abbe Fetel’ (7.1%), ‘Butira Precoce Morettini’ (5.5%), ‘Santa Maria’ (5.1%), ‘Poire de Cure’ (4.9%), ‘Beurre Hardy’ (3.5%), ‘Packam’s Triumph’ (2.2%) and ‘Clapp’s Favourite’ (1.9%). The average number of trees per ha is 1,267. Of the total number of registered trees only 9% are grown in the Adriatic Croatia, and the remaining 91% (781.8 ha) in the continental part of Croatia. In the past decade modern plantations have been gradually established on less vigorous rootstocks (mainly MC and less Adams and Sydo) with economically valuable cultivars such as ‘Abbe Fetel’ and ‘Conference’.

Structure and species diversity of traditional homegardens in Batticaloa district

A homegarden is part of a household livelihood strategy and has gained prominence as a natural asset through which sustainable use of resources, for the livelihoods of the poor, may be achieved. Despite the benefits, homegardens in the Batticaloa district have not been evaluated in-depth. This study focused on the composition, structure, diversity and different systems of homegardens in the Batticaloa district. The study was conducted in three Divisional Secretariat divisions in the district where 206 samples were collected. Results of the study revealed that average number of trees per household was 6.56. Species richness, varied from 2- 56 with the mean of 12.93. Mean Shannon index was 0.66. Two different types of systems were identified viz., Single layered and Multi layered systems. Single storied system composed only of banana or cashew or coconut trees. Only 23% homegardens were classified as single layered system while the rest were multi layered system. DOI: http://dx.doi.org/ 10.4038/jas.v9i3.7436 The Journal of Agricultural Sciences, 2014, vol.9, no3: p.139-146

한국과 중국의 마을비보숲 식생 비교 - 한국(韓國) 진안(鎭安)과 중국(中國) 청주(靑州)를 사례로 -

본 연구는 한국과 중국의 마을 비보숲의 식생을 비교하기 위하여 수행되었다. 이를 위하여 한국과 중국의 대표적인 마을 비보숲이 잔존하는 지역을 예비조사를 통해 확인하여 한국의 진안과 중국의 청주를 선정하였다. 주요 조사방법은 현장조사이고, 조사된 두 지역에 대한 비교 고찰을 위하여 빈도분석이 이루어졌다. 이를 통해 두 지역의 차이로 인해 마을 비보숲의 식생의 특성에 있어서 많은 차이가 있는 것으로 나타났다. 분석결과, 두 지역의 평균 종수는 2.9종으로 같았다. 그러나 평균 개체수, 총 개체수, 입목밀도는 청주가 진안에 비해 상당히 큰 것으로 나타났다. 또한 수고, 평균 흉고직경, 수관폭은 진안이 청주보다 상당히 큰 것으로 나타났다. 그리고 임상과 주요 수종 역시 매우 다른 것으로 나타났다. 따라서 본 연구를 통해 한국과 중국의 특성을 살린 마을 비보숲의 복원과 관리의 정책 방향을 마련하는 데 도움이 될 것으로 사료된다. The purpose of this study is to compare the vegetation structure in complementary forests of villages between Korea and China. For this study, Jinan in Korea and Qingzhou in China were selected through a pre-survey about the representative regions of both countries. The main research method used was field study. A comparative analysis between the two regions was performed by a frequency analysis of the surveyed data. The data obtained in the study shows the vegetation structure in complementary forests of villages in the two regions have many differences which are related to the local culture. As a result, it was identified that the average number of species was the same at 2.9 and the average number of trees, total number of trees, and tree density in Qingzhou were considerably greater than those in Jinan. Also, it was identified that tree height, average breadth height diameter and crown width in Jinan were considerably greater than those in Qingzhou. Furthermore, it was identified that both the forest state and the principal species of tree are both very different according to the different cultures. Through this identification, it is considered that this study will be helpful in establishing policy direction in both countries about the restoration and management of complementary forests.

Incidence and spread of Heterobasidion root rot in uneven-aged Norway spruce stands

Notwithstanding Norway spruce (Picea abies (L.) Karst.) is highly prone to root rot caused by Heterobasidion parviporum Niemelä & Korhonen, but little is known about the epidemiology of Heterobasidion root rot in spruce stands applied to uneven-aged management. To get insight into the development of Heterobasidion infections in this type of forest, the size and spatial distribution of individual genets of H. parviporum were determined in five uneven-aged managed Norway spruce stands in southern Finland. In these stands, all tree size classes (regeneration, intermediate, and overstory trees) were infected by H. parviporum. The average number of trees and stumps infected by a single genet ranged from 3 to 6.3 (mean 4.4) among study plots. All Heterobasidion genets identified from overstory trees or stumps had spread to the younger tree generation. Secondary infection from overstory trees was the main way of infection (at least 85% of all infections) among the regeneration and intermediate trees. The results indicate that uneven-aged management strategies that maintain continuous spruce regeneration favour the secondary spread of H. parviporum between different tree size classes and may compromise the production of high-quality timber over successive generations.

Quantifying spatial patterns of tree groups and gaps in mixed-conifer forests: Reference conditions and long-term changes following fire suppression and logging

Fire suppression and past logging have dramatically altered forest conditions in many areas, but changes to within-stand tree spatial patterns over time are not as well understood. The few studies available suggest that variability in tree spatial patterns is an important structural feature of forests with intact frequent fire regimes that should be incorporated in restoration prescriptions. We used a rare dataset consisting of mapped locations for all trees ⩾10cm in three 4-ha plots in 1929 before logging and in 2007/2008, 78 and 79years after logging, to assess changes in three spatial components of forest structure: individual trees, tree clusters and gaps. Comparing 1929 old growth to modern conditions, area in gaps decreased from 20% to zero, the percentage of stems that were single trees from 6% to 2% and in small or medium clumps (2–9 trees) from 28% to 9%, while trees in large clumps (⩾10trees) increased from 66% to 89%. Concurrent with these changes, canopy cover increased from 45% to 62%, and the average number of trees in a clump increased from 11 to 26, resulting in much more homogenous conditions across the stand. These changes also altered tree size and species associations within different structural groups (i.e., single tree, small, medium and large clumps). In an effort to account for the alteration of the fire regime that had already taken place in 1929 (the last fire recorded in tree rings was in 1889) we also analyzed spatial patterns of 1929 conditions removing all trees <25cm. In this analysis, 35% of the plot area was in gaps and canopy cover averaged 36%. Tree clusters had an average of 5.2 trees per clump, with 13% of trees being singles, 30% in small clumps, 24% in medium clumps and 33% in large clumps. Our results provide metrics that quantify spatial patterns and composition of individual trees, tree clumps, and gaps under the historical fire regime that may be useful to forest managers. Our study demonstrates that the contemporary forest is more homogeneous than it was historically, and variability that likely provided diverse microclimate and habitat conditions and fostered resilience to a variety of stressors and disturbances such as fire, insects and drought has been lost. Future management may benefit from restoring these structural components.

Simplified, empirical model of wind speed profile under canopy of Istebna spruce stand in mountain valley

The wind speed in a forest is one of the main factors deciding upon the amount of water balance between the atmosphere and the soil. Inside a forest complex, the distribution of vertical wind speed has a characteristic S-shape. This paper presents a simplified, empirical model of such an S-shaped wind profile within a stem layer of an Istebna spruce stand. Measurements of the wind speed were taken at four levels in 9 homogeneous, even-aged stands of different age-class: from a 10-year-old natural seeding to a 121-year-old mature stand. Recorded data unambiguously confirmed the existence of the secondary maximum inside the stem layer. The main aim of this paper was to make all model parameters conditional on biometrics features of tree stand as well as the geographical location of research sites on the slopes in a mountain valley. All parameters describing the simplified, empirical model of S-shaped wind profile within the stem layer strictly depend on the well-known total basal area TBA [m2h−1]. TBA is determined by only an average number of trees per hectare and a mean diameter at a breast height, i.e. 130cm above ground, which are easy to be measured with high accuracy ‘from ground’. Presented data analysis shows that the estimated wind speed at the secondary maximum and a mean wind speed within a stem layer are contingent upon a biomass density in the crown layer and its elevation above ground. A biomass density can be equated with the leaf area index (LAI).The presented simplified, empirical model of the vertical wind speed profile for a spruce stand and its parameterization scheme, which is to be measured in an effortless way, should be easily adaptable to stands composed of other tree species, taking into consideration specific differences between spaces. The necessary improvements of the presented empirical model would be possible after some series of measurements taken within various types of tree stands. A thorough understanding of the biological factors creating the observed S-shaped wind profile ought to considerably expand the knowledge of the forest ‘ventilation’ process, which determines vaporization from the soil as well as the CO2 advection.

Modelo de Clutter na modelagem de crescimento e produção de eucalipto em sistemas de integração lavoura-pecuária-floresta

O objetivo deste trabalho foi definir a melhor forma de uso do modelo de Clutter para estimar o crescimento e a produção de clones de eucalipto em sistemas de integração lavoura-pecuária-floresta. Foram utilizados dados de sistemas de integração localizados na região noroeste do Estado de Minas Gerais. Os dados foram originados a partir de 180 parcelas permanentes de inventário florestal contínuo, de 30x40 m, contendo três fileiras de dez árvores, com amostragem casual estratificada de intensidade de uma parcela para cada 10 ha. O número médio de árvores por hectare foi de 242. Foram avaliadas plantas com idades de 20 a 95 meses. As melhores relações funcionais foram obtidas a partir do uso do modelo original de Clutter, com base na significância e nos sinais esperados das estimativas de seus parâmetros. O ajuste do modelo de Clutter deve ser feito na sua forma completa.

Suburban sprawl: environmental features affect colony social and spatial structure in the black carpenter ant, Camponotus pennsylvanicus

1. In social insects, the number of nests that a colony inhabits may have important consequences for colony genetic structure, the number of queens, sex allocation, foraging efficiency, and nestmate recognition. Within the ants, colonies may either occupy a single nest (monodomy) or may be organised into a complex network of nests and trails, a condition known as polydomy. 2. The current study is a large-scale, long-term, comprehensive field examination of various features of colony social and spatial structure in the facultatively polydomous black carpenter ant, Camponotus pennsylvanicus (DeGeer). The study examined the density, persistence, and the spatiotemporal distribution of colonies across a gradient of land disturbance associated with urban development. The temporal and spatial pattern of nest use was compared between fragmented landscapes where nesting sites were interspersed among human-built structures (urban plots) and less disturbed landscapes with higher tree density (suburban plots). In addition, nesting site fidelity and changes in colony spatial structure were monitored over 7 years. 3. Long-term monitoring and extensive sampling over a large spatial area allowed the first comprehensive insight into the spatiotemporal dynamics of colony and population structure in C. pennsylvanicus. A total of 1113 trees were inspected over 233 ha. Camponotus pennsylvanicus were active on 348 of the 1113 trees (31%) and these represented 182 distinct colonies. The colonisation rate remained relatively stable over 7 years suggesting that an equilibrium point had been reached. Relative to the suburban plots, tree density was 65% lower in the urban plots. The proportion of trees colonised by C. pennsylvanicus was significantly higher in the urban plots suggesting that intraspecific competition for nesting sites may be especially high in areas with lower tree density. Colony spatial structure also differed significantly between habitats and a higher incidence of monodomy was observed in the urban environment. The average number of trees per colony across all subplots was 1.95 (range 1–4) indicating that C. pennsylvanicus are weakly polydomous. 4. The composite picture that emerges for C. pennsylvanicus colonies in the urban habitat is a chain reaction of events: (i) the urban habitat has a lower tree density, (ii) lower tree density results in higher tree colonisation rate, (iii) higher tree colonisation rate results in simpler colony spatial structure (i.e. higher incidence of monodomy), and (iv) simpler colony spatial structure results in numerically smaller colonies. Long-term monitoring of the spatiotemporal pattern of nest site use in selected colonies revealed a unique trend. While worker counts in selected colonies remained relatively stable throughout the course of the study, colony spatial structure changed considerably with 28% of colonies experiencing a change. Furthermore, the likelihood of detecting a change in colony spatial structure increased with the amount of time passing from the initial inspection. 5. In conclusion, tree density has a significant effect on a number of important colony features in C. pennsylvanicus. Besides tree density, other environmental features such as human-built structures cause habitat fragmentation and may act as natural barriers to worker dispersal and/or foraging. Such barriers may ultimately affect the social and/or spatial structure at both the colony and the population level.

Effects of population density on forest structure and species richness and diversity of trees in Kampong Thom Province, Cambodia

This study examined differences in stand structure, tree species richness, and tree species diversity in relation to population density in Kampong Thom Province, Cambodia. Tree data were obtained from a 1997 forest inventory involving 60 clusters (540 plots) systematically distributed over 30% of the provincial forest area. Spatially referenced population data were obtained from the 1998 national population census. The average number of trees per cluster was 356/ha, the average basal area, 23 m2/ha, the average stand volume, 217 m3/ha, and the average aboveground biomass, 273 Mg/ha for all trees of DBH 10 cm and larger. The average species richness per cluster was 37 species, while average species diversity was measured as 0.916 using Simpson’s index and 2.98 by Shannon’s index. Significant negative correlations were generally found between population density surrounding clusters and tree density, basal area, stand volume, aboveground biomass, and species richness and diversity for three examined diameter classes (DBH of 10–30, ≥30, and ≥10 cm). As the distance from clusters for calculating population density increased, the correlation levels increased up to 5 or 7 km, depending on the variables and diameter class, and then stayed relatively constant for stand structure variables and decreased for species richness and diversity. The results indicate that evidence of disturbance was more pronounced at higher population density up to around 5 to 7 km. We suggest that introduction of greater controls on human disturbance should be a high priority for resource management and conservation in Kampong Thom Province and, presumably, Cambodia as a whole.