Comparison of sustainable forest management (SFM) trends at global and country levels: case study in Iran

Sustainable Forest Management (SFM) is an integral component of sustainable development. Iran is a Near East country with low forest cover. Iran uses 7 criteria and 65 indicators for regional and national monitoring of forest management. We evaluated the status of SFM in Iran, and a location imaging in its path towards SFM was provided by existing validation data and library references for the Criteria and Indicators (C&I) adopted in the Near East, We identify challenges and opportunities associated with SFM in Iran. Although the information to evaluate the trend of SFM in Iran was incomplete, we compiled some information on the basis of C&I. Comparison of some indicators with the values for the rest of the world revealed that the situation in Iran is very different. Although some indicators revealed a better situation in Iran, Iran lags the rest of the world in the implementation of SFM. Iran, like many countries, is trying hard to find ways to sustainably use its forests. Not all C&I for assessment of SFM in Iran have been determined or defined. However, a consistent and comprehensive framework of criteria and indicators to monitor progress towards SFM is being applied. Defining some C&I is still at an early stage.     

Natural regeneration of oriental beech(Fagus orientalis Lipsky)trees in canopy gaps and under closed canopy in a forest in northern Iran

For developing nature-based silvicultural practices in a beech forest to promote, abundance, height,vitality, and preferred growth form, regenerated trees growing in gaps were compared with those under closed canopies.A systematic 50×50 m grid was plotted in a beech stand in the Kheyrud Experimental Forest for selecting trees to measure variables in gaps and under closed canopies.Abundance and mean height of regenerated beech trees were significantly higher in closed canopies than in canopy gaps.Beech seedlings with excurrent growth were significantly taller within regeneration patches under closed canopy.Moreover, regenerated trees with high vitality were more abundant in closed canopy areas than in gaps.Thus, beech regeneration should improve under closed canopies; hence, gaps in a near natural forest should be created only after adequate regeneration and appropriate growth under the parent tree in a closed canopy area is ensured.The results of this research have profound implications for the sustainable management of the forest and for ensuring sustainable beech regeneration.The presence of a closed canopy cover likely will reduce potential stresses on oriental beech regeneration.     

Effects of foliage and traffic intensity on runoff and sediment in skid trails after trafficking in a deciduous forest

After ground-based skidding operations, soil particles are rearranged closer together resulting in increased bulk density, reduced total porosity, and decreased infiltration capacity. The aim of the present study was to assess and quantify runoff and sediment in both leafed and leafless periods (foliage) over a 1-year duration following three levels of skidder traffic intensity (low, medium, high) performed in the Hyrcanian forests, Iran. By increasing traffic frequency, soil bulk density increased significantly, whereas total porosity decreased as compared to undisturbed (control) plots. After trafficking, runoff and sediment yield were significantly affected by foliage and traffic frequency. Regardless of foliage, mean total runoff and sediment increased with increasing traffic frequency performed on the skid trail. Mean runoff in the low, medium, and high traffic plots in the leafless period were 95.5, 54.2, and 21.7% higher than the values of runoff in the leafed period, respectively. Mean sediment yield in the low, medium, and high traffic plots in the leafless period was 7.1, 5.1, and 3.3 times higher than the values of sediment in the leafed period, respectively. Based on regression analysis, the runoff and sediment response to rainfall for the control plots and three traffic intensity classes were linear and statistically significant for both leafless and leafed periods. The total runoff in the high traffic intensity plot was 239.8 mm (62%) during the leafless period, and 38% of total runoff (148 mm) occurred during the leafed period. The sediment response to runoff over both leafless and leafed periods at all the traffic intensity classes and control plots were significantly linear. Restricting ground-based skidding operations to trail segments where the machine traffic is less than 4 (low)—9 (medium) traffic cycles can be effective to reduce runoff and sediment over compacted soil after machine-induced traffic.     

Over-mature beech trees (Fagus orientalis Lipsky) and close-to-nature forestry in northern Iran

Oriental Beech is the most important commercial tree species in northern Iran. In recent years wood production companies interested in felling large beech trees for profit have challenged advocates of close-to-nature silviculture who favor conservation. Our study objective was to assess the economic value of over-mature beech trees by relating tree diameter (DBH) to amount of decay. Based on the location of onset of decay, we categorized three types of decay as stump, stem, and crown decay. Trees of greater diameter (age) typically showed greater decay in the stem. Percent of decayed volume, diameter of decayed tissue, and length of decay in tree stems varied between 0.5%?64.3%, 15 cm?75 cm, and 2.0?19.5 m, respectively. With increasing trunk diameter, the proportion of truck decay increased. Red heart and dark red heart constituted 25% and 14.3% of sampled trees, respectively. However, we found no correlation between intensity of stem decay and morphological characteristics of trees. Seedlings were not abundant around the bases of over-mature trees, suggesting that the trees did not contribute to regeneration of the stand. Beech trees of diameter >1 m do not provide valuable round wood for industries and cause to raise wood production costs. We recommend that these trees >1 m DBH should be retained in forest stands because of their low commercial value but high ecological and conservational values such as maintaining biodiversity in forest ecosys-tems.     

Canopy gaps and regeneration in old-growth Oriental beech (Fagus orientalis Lipsky) stands, northern Iran

Virgin beech Fagus orientalis forests in northern Iran provide a unique opportunity to study the disturbance regimes of forest ecosystems without human influence. The aim of this research was to describe characteristics of natural canopy gaps and gap area fraction as an environmental influence on the success of beech seedling establishment in mature beech stands. All canopy gaps and related forest parameters were measured within three 25 ha areas within the Gorazbon compartment of the University of Tehran’s Kheyrud Experimental Forest. An average of 3 gaps/ha occurred in the forest and gap sizes ranged from 19 to 1250 m² in size. The most frequent (58%) canopy gaps were <200 m². In total, canopy gaps covered 9.3% of the forest area. Gaps <400 m² in size were irregular in shape, but larger gaps did not differ significantly in shape from a circle. Most gaps (41%) were formed by a single tree-fall event and beech made up 63% of gap makers and 93% of gap fillers. Frequency and diversity of tree seedlings were not significantly correlated with gap size. The minimum gap size that contained at least one beech gap-filling sapling (<1.3 m tall) was 23.7 m². The median gap size containing at least one beech gap-filling sapling was 206 m² and the maximum size was 1808 m². The management implications from our study suggest that the creation of small and medium sized gaps in mixed beech forest should mimic natural disturbance regimes and provide suitable conditions for successful beech regeneration.     

Stand characteristics of mixed oriental beech (<Emphasis Type="Italic">Fagus orientalis</Emphasis> Lipsky) stands in the stem exclusion phase,northern Iran

The structure of forest stands changes through developmental phases. This study is carried out in the unmanaged, oriental beech (Fagus orientalis Lipsky) stands in the north of Iran. The aim of this research was to quantify structural characteristics of stands in the stem exclusion phase using common structural indices, which include mingling, tree–tree distance, stem diameter, and tree height differentiation. According to our measurements from three stands, naturally regenerated stands tend to be mixed in species composition have slightly heterogeneous diameter distributions and uniform tree height. The average distance between trees was 3.3 m. Stocking volume of the stands had an average of 540 m³ ha^?1 and 412 stem ha^?1. Dead wood volume was 24 m³ ha^?1, and as a standing volume, the most frequent species in dead wood pool was oriental beech (F. orientalis) (48 %). The common form of dead trees was snag (41 %). The mean value of mingling and tree-to-tree interval indices revealed that beech was mixed intensively with hornbeam and appears to be a more successful competitor for space and light compared with hornbeam; moreover, we found relatively high evidence of inter-species competition in this phase. A better understanding of stand characteristics in the stem exclusion phase as a critical part of the natural dynamics of forest ecosystems could facilitate predictions about the future changes within the stand.     

Effects of litter and straw mulch amendments on compacted soil properties and Caucasian alder (Alnus subcordata) growth

New Forests - Application of mulch on compacted soil is a common engineering measure to suppress runoff and soil loss during ground-based mechanized forest operations. Despite the expanded use,...     

Genetic fingerprinting of Iranian Xanthomonas campestris pv. campestris strains inducing black rot disease of crucifers

Northern Iran has one of the largest and most diverse populations of cultivated crucifers in Iran. Symptoms of black rot disease were observed in 40 % of fields. To assess the genetic diversity of Xanthomonas campestris pv. campestris (Xcc) strains, associated with black rot disease, 40 strains were isolated from infected samples of crucifers such as cabbage, radish, cauliflower, turnip and kohlrabi, and were collected from different geographic regions of northern Iran including West and East Azarbayjan and Ardabil provinces. Bacterial strains were characterized by their morphological, biochemical and physiological features and pathogenicity tests. Four races were found in northern Iran (1, 4, 5 and 6) and the majority of the tested strains belonged to either race 4 (45 %) or race 6 (20 %). To examine the distribution of dispersed repetitive DNA, Enterobacterial Repetitive Intergenic Consensus (ERIC), BOX, Repetitive Extragenic Palindromic (REP) and random amplified polymorphic DNA (RAPD) sequences in the genome of Xcc using conserved primers. The different markers produced characteristic banding patterns and the similarity matrices from binary banding data was derived with the similarity for qualitative data program (SIMQUAL). On the basis of the fingerprint patterns generated by the combination data set of both rep-PCR and RAPD, the Xcc strains were differentiated into seven clusters (A–G) at 76 % similarity level. The geographical origin of the Iranian strains does not seem to be correlated with the RAPD and rep-PCR clusters. The clusters seem to be more related to the race of the strains. This is the first study on genetic diversity of Xcc strains inducing black rot disease of crucifers in Iran.