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 ...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 propor- tion 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 charac- teristics 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 valu- able 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 ecosystems.展开更多
Close-to-nature forest management has been proposed as an effective method for improving the quality of plantation forests. Knowledge of spatial distribution patterns, structure, and succession trajectories in natural...Close-to-nature forest management has been proposed as an effective method for improving the quality of plantation forests. Knowledge of spatial distribution patterns, structure, and succession trajectories in natural forests can provide guidelines for the establishment of close-to-nature forest plantations. Such knowledge is lacking in natural spruce(Picea crassifolia) forests in the Qilian Mountains of China, impeding the establishment of production forests. We conducted a case study in the Qilian Mountains to analyze the relationships between the naturally-formed forest patches and terrain factors, spatial heterogeneity of stand characteristics, and stand structure following harvesting disturbance. Our results suggested that spruce plantations will be effective on the N, NE, and NW slopes, at elevations between 2700 and 3300 m, and on slopes ranging from 15° to 45°. Further, planted forest patches should occupy 64% of the slope area on semi-shady slopes(NE, NW). Spatial patterns in the studied forest exhibited a strong scale-effect, and an area of 0.25 ha could be used as the most efficient plot scale for the management of spruce plantations. Partial logging is an effective method for the conversion of spruce planted forests into nearnatural forests, and the intensity of partial logging can be determined from the negative exponential function relationship between stand density and DBH. Our results provided critical information for the development of spruce plantations and conversion of existing plantations.展开更多
文摘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 propor- tion 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 charac- teristics 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 valu- able 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 ecosystems.
基金supported by the National Natural Science Foundation of China(Grant Nos.41522102,41701296,and 41601051)the CAS“Light of West China”Program
文摘Close-to-nature forest management has been proposed as an effective method for improving the quality of plantation forests. Knowledge of spatial distribution patterns, structure, and succession trajectories in natural forests can provide guidelines for the establishment of close-to-nature forest plantations. Such knowledge is lacking in natural spruce(Picea crassifolia) forests in the Qilian Mountains of China, impeding the establishment of production forests. We conducted a case study in the Qilian Mountains to analyze the relationships between the naturally-formed forest patches and terrain factors, spatial heterogeneity of stand characteristics, and stand structure following harvesting disturbance. Our results suggested that spruce plantations will be effective on the N, NE, and NW slopes, at elevations between 2700 and 3300 m, and on slopes ranging from 15° to 45°. Further, planted forest patches should occupy 64% of the slope area on semi-shady slopes(NE, NW). Spatial patterns in the studied forest exhibited a strong scale-effect, and an area of 0.25 ha could be used as the most efficient plot scale for the management of spruce plantations. Partial logging is an effective method for the conversion of spruce planted forests into nearnatural forests, and the intensity of partial logging can be determined from the negative exponential function relationship between stand density and DBH. Our results provided critical information for the development of spruce plantations and conversion of existing plantations.
