Biomass Expansion Factors (BEFs) and Carbon Stock for Brant's Oak (Quercus brantii Lindl.) Forests in West-Iran

Investigating a tree’s biomass can provide basic information about forest carbon stock. The Biomass Expansion Factor (BEF) is a variable for estimating carbon stock of forests. The aim of this study was to analyse the Above Ground Biomass (AGB) allocation, developing the BEF and carbon stock for two vegetation forms of Brant’s Oak (Quercus brantii Lindl.) based on forest inventory data. BEF is defined as the ratio of AGB to crown volume variables. The study data were taken from 30 trees that include 16 individual trees with single stem and 14 coppice shoots located in West-Iran. The trees selected were felled and separated into different components including: bole, main branches, lateral branches, twigs and leaves. The fresh weight of the trees was obtained with a portable hanging scale and several samples were taken from each tree component. The results of this study showed significant differences between component biomass proportions of the two vegetation forms of Brant’s Oak trees and determined average biomass and carbon content of the forms studied. We also conclude that BEF of Brant’s Oak could be improved by applying crown variables. According to the results, BEFs are tree-size dependent variables. Finally, this study indicates that age-dependent BEFs cannot be applied to conditions where stand development deviates from the conditions that in which the BEFs were developed

Co-limitation towards lower latitudes shapes global forest diversity gradients

The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from ~1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers

Site demands and life habitat of Maple "Acer velutinum Boiss." in northern forests of Iran

The present investigation is carried out in deciduous mixed forests of Caspian region in north Iran. 18 sample plots each with three and more Maple trees were established from 100 m. a. s. l. up to 2000 m. a. s. l. Moreover, 12 soil profils were studied in the Maple stands of the research area. Totally 248 Maple trees were studied quantitavely and qualitatively. The results showed that Acer velutinum Boiss. (very similar to Acer pesudoplatanus L.) is a light demand tree species which normally appears as groups in the young stage. In adult stage Maple appear as individual trees in the upper layer of mature stands. Nevertheless, Maple individuels and groups were distributed to a variety of soil types ranging from caly soils with poor drainage (marmorized brown soil) to well drained loam/sandy soils (calcic brown soil). The root system of this species is deep with maximum root density between 40 cm and 65 cm of soil depth. Although Maple grows in Oak-Hornbeam (Querceto-carpinetum betuli) stands with campact and heavy soil, but it founds its optimal growth conditions in beech stands (Fagetum hyrcanum) on gentle slopes with well drained soils reach in skelet. Here were the rate of annual diameter and height increment of Maples with mean age of 33 years, 10.1 mm/year and 84 cm/year respectively. Seed fall and regeneration of Maple occurs every year and easily. One year old Maple seedlings are very common on the forest ground flora. Due to light demands of Maple seedlings and ground flora competition, the survival of the seedlings is not very high. Generally, the plant number were reduced by decreased canopy density. In areas with>0.7 crown canopy density, the mean number of Maple seedlings decreased from 5.3/m2 to 0.4/m2, during one year. In areas with < 0.7 crown canopy density, the mean number of Maple seedlings were higher than the first one and decreased from 13.9/m2 to 0.7/m2

Silvicultural characteristics and site demands of Gall Oak (Quercus infectoria Oliv.) in Shineh, Lorestan province Iran

Gall oak (Quercus infectoria Oliv.) is one of rare species that is only presence in the northwestern part of Zagros mountains. This research aims at studying site demands and some quantitative and qualitative characteristics of Qurecus  infectoria. For this purpose, the distribution area of this species was studied in Lorestan province in western Iran. Twenty four sample plots, each 1000 m2, were established in 3 land forms (ridge, valley and slope), in 4 aspects (north, east south and west) and in 2 altitudes level (1200-1600 and 1600-2000 m.a.s.l.). Also the chemical and physical properties of soil in the sample plots were studied. The results showed that the surface of distribution area of Gall oak is 5751 ha and its extended from 1200 to 2400 m.a.s.l. The soil of oak sites were usually light (loam) to heavy (clay) with a pH between 7.4 and 8.0 . Organic matter is realtively good and EC is insignificant in the studied site soils. In general, slopes and vallies with north aspect in altitude between 1200 and 1600 m.a.s.l.  are suitable sites of this oak spieces. The highest oak tress were observed on north faced vallies (7.7m), the longest trunk length (3.2 m), the widest crown diameter and also the highest proportion of oak trees with good quality (75%) were assessed all observed on north faced slopes

Application of bivariate Ripley's K- function for studying competition and spatial association of trees (Case study: intact Oriental beech stands in Kelardasht)

Competition is a fundamental ecological process driving succession in a forest and affects on forest stand structure. Understanding competition among tree species is especially important when management goal is to mimic the dynamics of natural ecosystems. Three 1-ha stem-mapped plots were established at three developmental stages of initial, optimal and decay in an intact natural, unmanaged and uneven-aged beech (Fagus orientalis Lipsky) forest in the Kelardasht region, in the north of Iran. Diameter of all trees with dbh greater than 7.5 cm were recorded. All of the measured trees were assigned into four diameter size classes as small, medium, large, and extra large timbers. Spatial associations among tree size classes were analyzed using bivariate Ripley’s K-function. Results showed that association patterns (i.e., attraction and repulsion) varied among different size classes across different development stages, likely influenced by shade-tolerance characteristics, seed dispersal limitation and intra-specific competition of beech trees. This study highlighted the application of bivariate Ripley’s K-function and the importance of competition in understanding stand dynamics of beech forests across development stages. The information derived from these untouched stands could be useful as a key reference for developing management programs, silvicultural interventions, plantations and reforestation programs as well as giving us insight into competitive processes to enable better modeling of beech stands dynamics

Development stages and dynamic of two oriental beech (Fagus orientalis) communities at natural forests of Kheiroudkenar-Noshahr

Considering the morphological characteries of trees and the structure of stands, different development stages could be recognized in natural untouched forests. The development stages as well as the dynamic of the stands are basic references for application and development of nature based silvicultural  interventions. The aim of this research was to study the structure, qualitative and quantitative chareateristics of the main development stages (initial, optimal and decay) in two different plant communities of oriental beech forests, in the Caspian region. For this purpose two communities of Rusco-Fagetum and Carpineto-Fagetum in the experimental forest of Tehran University (Kheyroudkenar-Noshahr) were selected. In each community three sample plots, each one ha, were established and tree spieces, diameter and height of all trees were assessed. Moreover, one transect (10*100) was selected in each sample plot and the structure (vertical and horizontal profile) of the stand was studied. Results showed that all three stages could be recognized in the pure beech community, while the optimal stage has not been occured yet in the mixed beech–hornbeam community. Distribution of stem number, basal area and volume in different diameter and height classes of all development stages are given in this paper

Investigation on some silvicultural and habitat characteristics of Quercus macranthera F. & M. at Semnan Province of Iran

Quercus macranthera is a dominant tree species of high elevation parts of north  forests of Iran (Caspian region). It is distributed at high elevation area of Semnan and Shahrood cities of Semnan province at two types: 1. Scattered between 1700 and 2000 m. a.s.l. and 2. dense as dominant species between 2000 and 2500 m. a.s.l. and often on north aspects. In onder to study the silvicultural characteristics and site demands of this species, 42 sample plots were laid out on different land forms and geographical aspects, which In 34 plots, soil properties, including texture (clay, sand and loam), organic carbon, lime and acidity were studied. The results showed that pH varied between 5.2 and 8.1 and soil texture was almost sandy clay loam in all land forms, with an exception of clay loam on ridges. soil texture on north and east aspects was sandy clay loam, whereas on south and west aspects was loamy. Organic carbon percentage at three humid aspects (north, east and west) was 1.57, 1.69 and 1.95 %, respectively, whreas at south aspect was 0.48 % and significantly different from the other three aspects (p< 0.05). The maximum and minimum percentage of lime was 20 and 0.9 at south and west aspects, respectively with significant difference (

Site demands and some quantitative and qualitative characteristics of Persian Oak (Quercus brantii Lindl.) in Chaharmahal & Bakhtiari Province (western Iran)

This research was carried out at three sites, including lordegan, Ardal and Bazoft of Chaharmahl and Bakhtiari province, where the oak monna (Quercus branttii Lindl.) is the dominant tree species. First of all, forest types were sutdied, which Q. brantii was the main forest element. Tehn three sites at north west, west and south west of the province, where are the main habitats of Oak manna, were selected and 12 plots of 1000 m2 surface area were allocated at each site, including three land forms (valley, slope and ridge) and four main slope aspects (north, south, east, west). Overall, 36 plots were allocated and site demands, soil physical and chemical properties and tree quantitative and qualitative characteristics were studied at each plot. The results showed that the Oak manna is a light demanding species with highest distribution on south western slopes at 1800 to 2000 m. above sea level. Soil pH varied from 7.7 at soil surface to 7.85 at deep layers. Total nitrogen and organic matter of soil was good and its salinity was not significant. Most of the Oak trees had a coppice regeneration form (84, 2-78-6 %). Averagely, each tree produced four to five sprouts. This indicates a severe impact of human on Oak forests. Diameter and height of Oak trees varied between 13.8-19 cm and 4.3-5.2 m, respectively due to variation in land form

Diameter and height increment process of oriental beech (Fagus orientalis) in natural Caspian forests; Kelardasht region

The development stages in the natural forests run very slowly, which are not easy to recognize them within a short period of time. The duration of development of a stand and transition from one stage to another varies among the forest communities. Also the growth characteristics and dynamic of the stands varies in different development stages. This paper aimed to study the diameter and height increment of oriental beech in relation to tree age within the stages. For this purpose, four beech trees in diameter from 15 to 70 cm, were selected and stem analysis were carried out in an interval of 1.4 m logs. The results showed that the diameter increment has no uniform pattern and varies with the age of tree and the development stage of the stand. The diameter and height increment of young beechs are very slow at the early stage of growth (up to the age of 30), which starts to increase later. A beech tree with a diameter of 12 cm could be 30 years old and could reach to a height of 12 m. While, another beech tree with a diameter of 40 cm could be 140 to 150 years old and the total height of such tree could reach to 25 m. The development (successional) cycle of oriental beech in the Caspian region, which occurs with establishing of seedlings within the gaps after falling of old trees and continues up to physiological death of trees, is estimated between 200 and 230 years. At this age the diameter of tree could reach to 70 cm

The structure of natural oriental beech (Fagus orientalis) forests in the Caspian region of Iran and potential for the application of the group selection system

ISSN:0015-752XISSN:1464-362