Combination of UAV Photogrammetry and Field Inventories Enables Description of Height-Diameter Relationship within Semi-Arid Silvopastoral Systems

Pollarding oak trees is a traditional silvopastoral technique practiced across wide areas of the northern Zagros mountains, a unique and vast semi-arid forest area with a strong cultural and ecological significance. So far, the effects of pollarding on tree structure in terms of DBH (diameter at breast height)~H (height) relationships within the typical pollarding cycle, which often lasts 4 years, has not been scientifically described. Here, we combine field inventories of DBH with H obtained from photogrammetric UAV flights for the first time to assess DBH~H relationships within this system. We conducted the research at six pollarded forest sites throughout the Northern Zagros. The sampling encompassed all three main species of coppice oak trees. In the case of multi-stem trees, we used the maximum DBH of each tree that formed a unique crown. A linear relationship between UAV and extracted H and the maximum DBH of pollarded trees explained a notable part of the variation in maximum DBH (R2 = 0.56), and more complex and well-known nonlinear allometries were also evaluated, for which the accuracies were in the same range as the linear model. This relationship proved to be stable across oak species, and the pollarding stage had a notable effect on the DBH~H relationship. This finding is relevant for future attempts to inventory biomass using remote sensing approaches across larger areas in northern Zagros, as well as for general DBH estimations within stands dominated by pollarded, multi-stem coppice structures

Estimation of acorn production by gall oak (Quercus infectoria Oliv.) in Baneh forests

Acorns provide important food sources for wildlife. In addition, they are traditionally used by forest dwellers and promote natural regeneration within forest ecosystems. However, a sufficient acorn mass is essential for a successful regeneration establishment. Here, we estimated acorn production of gall oak (Quercus infectoria Oliv.)trees in Kanybard in Baneh forests of Kurdistan province. Stand structure and general information were obtained from 20 square plots (20×20 m), which were scattered randomly in the study area. In a homogenous area of 80 ha, 80 sample trees were selected. To evaluate the effect of tree diameter and geographical aspect on acorn production, we selected two diameter classes (25 cm) nested in four main cardinal aspects (totally 8 levels). All acorns on each tree were collected at the end of 2013 growing season and were weighted in the field. In each level, 50 acorns were selected randomly, and their weight, length and width were measured. The results showed that geographical aspect does not affect acorn production. However, oak trees on northern and eastern aspects produce bigger and heavier acorns. In addition, tree diameter was found to positively affect acorn production, i.e. thicker trees produce more acorn. In average, each gall oak tree produces 1.907 kg acorn mass which varies between 0 to 19.87 kg in weight and 0 to 3088 acorns per tree. Our result indicated a weak acorn mast year for studied forest stands, which can help forest managers to evaluate and plan for acorn production in northern Zagros forests

Spiritual values shape taxonomic diversity, vegetation composition, and conservation status in woodlands of the Northern Zagros, Iran

Gefördert durch den Publikationsfonds der Universität Kasse

Response of Gall oak (Quercus infectoria Oliv.) to pollarding in northern Zagros

This study aimed to investigate the response of Gall oak (Quercus infectoria Oliv.) to pollarding. Therefore, a less-disturbed stand (1.4 ha) and a pollarded stand (1.7 ha) were selected. Five rectangular plots (20×30 m) were established in each selected stand by random sampling. In each plot, tree species, diameter at breast height (DBH), total height, trunk height and crown diameter for all trees (DBH ≥ 5 cm) were recorded. In addition, 18 tree samples were taken in each studied stands to assess the diameter increment of Gall oak. A pair of increment cores per sample tree was taken 50 cm above ground level, in which annual radial increment was measured and further multiplied by 2 to derive the annual diameter increment. Then, the diameter increment distribution of Gall oak trees in identical diameter classes was determined for the period of 1984-2010. The mean radial increment of two cores extracted from each sample tree was used in the calculations. The results showed that the average diameters, total height, trunk height, crown height and crown area were significantly lower (p < 0.01) in pollarded stands. Moreover, the averagee diameter increment in less disturbed and pollarded stands was estimated 1.32 and 2.08 mm per year, respectively. The results indicated that average diameter increment of Gall oak trees across he identical diameter classes during the studied period was significantly different between the examined stands

Comparison of seedling and coppice regeneration in pruned and undisturbed oak forests of Northern Zagros (Case study: Baneh, Kurdistan province)

Regeneration and forest durability guarantee is one of the most important aspects of forest sustainability and it should be placed in forest plans priority. So, due to important role of Zagros forests, comprehensive investigation about regeneration crisis becomes an increasing necessity. In this study we tried to investigate on seedling and coppice regeneration in two categories of higher and lower than 2 meters height classes and in untouched and traditionally pruned stands in three regions with different disturbance regimes. Study sites were located at Armardeh in Baneh city (Northern Zagros, Iran). Results of the study state that seedling and coppice regeneration in lower than 2 meters height classes are significantly more in untouched forest stands, and its density in site number "1" to "3" is 3250 versus 375± 92, 1600 versus 130± 18 and 310 versus 81± 37 per sample plot (2500 m2), respectively. In untouched stands in site number "1" and "2" saplings in higher than 2 meters height classes are 533 and 66 per sample plot., respectively, but in untouched stand in site number "3", due to livestock grazing, there is no sapling higher than 2 meters like other pruned stands. According to our results the most important factors affecting oak regeneration in this region are livestock grazing, fire, acorn collecting by villagers for domestic fodder, summer drought, pests and diseases on acorns and seedlings

Qualitative investigation of Gall Oak (Quercus infectoria Oliv.) acorns in untouched and pruned forest stands of Baneh (Kurdistan province, N-W Iran)

Due to encroachment and intense utilization, natural ecosystems of Zagros lost their normal trend and have converted to fragile and sensitive ecosystems. There are dense human populations that live in these forests which are depended on these forest resources. One of the most important utilizations in northern Zagros is Galazani (pruning) and using of oak limbs as fodder. This kind of use leads to prominent changes in forest structure and its physiognomy in some region (for example Alot in Kurdistan province) which can be a hazard for forest sustainability. Regarding to this problem and having no regeneration from seed, qualitative characteristics of Gall oak acorns, that is one of the most prominent species in these forests, was investigated in three untouched and pruned sites. Totally 60 Gall-oak trees (10 trees per site) and 6000 acorns (100 acorns per tree) were collected. Primary moisture of acorns in untouched sites was a little more than in pruned sites but there was no significant difference between them. The weevil Curculiogladium and Balaninusgladium were the insect species that predated the acorns collected from our sites. There were significant difference (in level of 95%) in the infestation rate among untouched and pruned sites of Blake, however in Ghole-shir and Mir-Yousef sites were no significant differences between insect-infested acorns. The weight of thousand acorns was significantly more in untouched sites; probably because of having more time to storing enough nutrients in their cotyledons. Germination percent and germination index data were analyzed by simple One Way ANOVA, and their averages were compared by Duncan test. There were no significant differences between germination percent of untouched and pruned sites. Comparing means indicate that, Blake site with 96.75 germination percent was placed in group A, Ghole-shir and Mir-Yousef sites were placed in group B with 90.78 and 88.75 germination percent, respectively. Germination index of untouched and pruned sites had no significant differences and in Duncan grouping they placed in one group. The values for germination index in Mir-Yousef, Blake and Ghole-shir sites were 13.18, 12.83 and 12.36, respectively

The impact of livestock grazing and canopy gaps on species pool and functional diversity of ground flora in the Caspian beech forests of Iran

Questions Livestock grazing is an important disturbance in many forest ecosystems. While several studies have addressed the general impact of different grazing and light intensities on temperate forest ecosystems, little is known about how the combination of these two factors can affect the species pool and functional diversity of temperate forests. Location Oriental beech forests of northern Iran. Methods Vegetation and environmental data of 104 releves were collected. These were assigned to four groups based on their light and grazing intensities. Non-metric multidimensional scaling was used to analyze vegetation compositional relationships among groups. We used nine functional traits related to growth, reproduction, and survival for a total of 147 plant species. Redundancy analysis of community-weighted means was used to determine the response of single traits to disturbance and environmental variables. Generalized additive models were applied to examine the shape of the response pattern of community-weighted mean trait values across the grazing and light intensity gradients. Functional richness and functional divergence indices were used to analyze functional diversity-disturbance relationships. Results Both light and grazing intensities significantly affected species pools, single traits, and functional divergence. Suites of trait attributes including hemicryptophytes, therophytes, grass-like, hygromorphic leaves, insect-pollinated, rhizomes, and runner plants were associated with high-light sites. In closed-canopy sites the strong filtering effect of shade resulted in suites of trait attributes including taller plants, macrophanerophytes, scleromorphic leaves, simple leaves, and berry fruits. While high-light sites had a larger species pool, they exhibited less functional diversity. Cattle grazing can mediate the filtering effect of light and increase functional diversity in both low-light and high-light sites. Conclusion Conservation measures in this region should acknowledge that moderate traditional cattle grazing combined with individual-tree and group-tree selection in these forests may maintain or even enhance functional diversity in these valuable ecosystems

Structure–Property Relationships of Nanosheeted 3D Hierarchical Roughness MgAl–Layered Double Hydroxide Branched to an Electrospun Porous Nanomembrane: A Superior Oil-Removing Nanofabric

A straightforward approach was successfully developed to fabricate a well-designed three-dimensional rough sheetlike MgAl–layered double hydroxide (LDH) array to stand vertically on poly­(acrylonitrile) porous nanofibrous membranes based on an electrospun-nanofiber-templated in situ hydrothermal strategy, and then the surface was modified with cyclohexanecarboxylic acid. The as-spun highly dense ordered sheetlike LDH porous nanofabric exhibited a superior durability in superhydrophobicity and superoleophilicity, which has achieved high oil-removing capability including both oil harvesting and oil separation to harvest/separate a wide range of organic solvents and oils from an oil–water mixture and, especially, exhibited a very good recycling and reusing performance. Interestingly, a steady water repellency was obtained against both drinkable hot (about 95 °C) and cool water. Outstanding oil harvesting, oil separation, and highly durable water repellant can be attributed to an effective synergistic effect between the high-density roughness of LDH nanosheets modified with acid and the very high porosity in the electrospun nanofibers, as well as the interspace between LDH nanosheets that acted as both a textile for selective oil separation and a container for penetrated oil storage, leading to special wettability, making the as-spun nanofabric a promising textile for large-scale removal and recollection of hydrophobic spillage on the water surface