| As the main type of forest classification management,the development of artificial commercial forest plays an extremely important role in ensuring wood ecological security,protecting natural forest,exerting the service function of forest ecosystem and promoting the sustainable development of forestry.With the implementation of a series of forestry projects and policies,China’s artificial forest area ranks first in the world and the construction of artificial commercial forest has been continuously promoted.However,China’s artificial commercial forest still has problems such as extensive management,low forest productivity,and low comprehensive benefits,so it is urgent to improve the quality and efficiency of the management of artificial commercial forest.This study uses the data of the fifth forest resources census in Hubei Province,based on the analysis of the artificial commercial forest resources in Hubei Province,applies the analytic hierarchy process(AHP)to construct an index system to evaluate the comprehensive quality and efficiency level of the artificial commercial forest in Hubei Province.And through the principal component analysis(PCA)of the evaluation indicators,the types of low-quality and low-efficiency artificial commercial forest are classified,the comprehensive quality and efficiency of the typical management models for improving the quality and efficiency of the artificial commercial forest in Hubei Province are investigated and evaluated,and suitable models for improving the quality and efficiency and key technologies of different types of low-quality and low-efficiency artificial commercial forest are proposed in order to provide technical support for the management of the artificial commercial forest in Hubei Province.The main research results are as follows:(1)The area of artificial commercial forest in Hubei Province is 2.8039 million hm~2,and the and the stock volume is 122.5699 million m~3.The area of timber forest is 2.1461 million hm~2,and the stock volume is 121.5941 million m~3.The area of economic forest is 0.6182 million hm~2,and the stock volume is 0.4596 million m~3.Artificial commercial forest in Hubei Province is mainly managed by timber forest(area accounting for 76.54%),followed by economic forest(area accounting for 22.05%),energy forest area is the smallest(accounting for 1.41%).The area of artificial timber forest and energy forest accounts for the largest proportion in Huanggang City(13.79%),and the smallest proportion in Ezhou City(0.45%),the area of economic forest accounts for the largest proportion in Yichang City(27.85%),and the smallest proportion in Ezhou City(0.28%).It can be seen that the distribution of artificial commercial forest in different administrative regions in Hubei Province is uneven and different.The area of artificial commercial forest with multi-purpose utilization as the management target is 1.2108million hm~2,accounting for 43.18%,and the stock volume is 62.7014 million m~3,accounting for51.12%,indicating that Hubei Province has rich types of artificial commercial forest.The area of forest land with grade IV protection of artificial commercial forest land accounts for the largest proportion(61.46%),but more than 20%of the forest land has not clearly planned protection grade,and forest land management needs to be further strengthened.The area of arbor forest accounted for 66.49%,and the total area of sparse forest land,shrub land and unformed forest land accounted for more than 20%,indicating that the development of artificial commercial forest as a whole still has a large space for improvement.The artificial commercial forest in Hubei Province is mostly pure forest,among which Pinus massoniana,Populus L,Quercus L,Cunninghamia lanceolata,Citrus L,Bamboo,Castanea mollissima,Camelliasinensis and Juglans regia L.account for more than 50%of the total area,which indicates that Hubei Province has a greater demand for the management of these tree species.Among the artificial timber forest and energy forest in Hubei Province,the area of young forest accounts for the largest proportion of the total area of artificial commercial forest(37.5%),followed by the area of middle-age forests(20.62%),and among the economic forest,the area of forest stand during the full fruiting period accounts for the largest proportion of the total area of artificial commercial forest(13.11%),indicating that the overall productivity of timber forest and energy forest is currently not high,the productivity of economic forest is relatively high,and most of them are in the critical period of management.(2)The comprehensive quality and efficiency evaluation index weights of artificial commercial forest obtained by AHP show that the weight of stand quality(0.729)in the target layer of the evaluation of timber forest and energy forest is much greater than the weight of stand benefit(0.271),indicating that forest stand quality has a greater impact on the comprehensive quality and efficiency.The weight of stand state(0.539)in the criterion layer is the largest,which has the greatest impact on the comprehensive quality and efficiency.The weights of average DBH(0.206),average tree height(0.160),community structure integrity(0.100)and tree volume per hectare(0.144)in the index layer all reach 0.100,indicating that these indicators are the key indicators to improve the comprehensive quality and efficiency of timber forest and energy forest.The weight of stand quality(0.692)in the target layer of economic forest evaluation is greater than the weight of stand benefit(0.308),indicating that stand quality has a greater impact on the comprehensive quality and efficiency of economic forest.The weight of stand state(0.470)in the criterion layer is the largest,which has the most obvious effect on the comprehensive benefit.The total vegetation coverage(0.298),the number of trees per hectare(0.172)and the economic forest production period(0.189)in the index layer have relatively large weights,all exceeding 0.100,indicating that these indicators are the key indicators for the potential improvement of comprehensive quality and efficiency of economic forest.(3)The comprehensive quality and efficiency evaluation results of artificial commercial forest in Hubei Province show that the number and area of the quartels with comprehensive quality-efficiency index of low-grade and very low-grade account for more than 35%,the number and area of the quartels with comprehensive quality-efficiency index of general-grade account for 26.59%and 29.91%respectively,the number and area of the quartels with comprehensive quality-efficiency index of high-grade and higher-grade account for 26.59%and29.91%respectively,indicating that the comprehensive quality and efficiency of artificial commercial forest in Hubei Province is general and there is a large room for improvement.The artificial commercial forest with high-grade comprehensive quality-efficiency index are mostly distributed in the central plain of Hubei Province,and the high-quality-efficiency forest is unevenly distributed.The number and area of the quartels with comprehensive quality-efficiency index,stand quality index and stand benefit index of low-grade and very low-grade of timber forest are 40.42%and 37.45%,36.62%and 35.85%,57.88%and 52.99%respectively,the number and area of the quartels with comprehensive quality-efficiency index,stand quality index and stand benefit index of low-grade and very low-grade of economic forest are 32.68%and 29.66%,23.29%and 22.73%,41.11%and 37.34%respectively,indicating that the comprehensive quality and efficiency level of economic forest in Hubei Province is slightly higher than that of timber forest and energy forest,but the overall comprehensive quality and efficiency level of these three types of forest are not high.In the index layer,the number and area of the quartels with the number of trees per hectare,shrub coverage,herbaceous coverage,age group grade,humus layer thickness,arbor volume per hectare and average DBH of low-grade and very low-grade among the evaluation indicators of timber forest and energy forest are more than 50%,the number and area of the quartels with the number of the average age,thickness of humus layer,thickness of soil layer,number of plants per hectare and herbaceous coverage of low-grade and very low-grade among the evaluation indicators of economic forest are more than 70%.It can be seen that poor growth,low vegetation coverage,unreasonable forest density and poor soil condition are the key technical problems to be solved to improve the quality and efficiency of the artificial commercial forest in Hubei Province.(4)The results of principal component analysis of comprehensive quality and efficiency evaluation index of artificial commercial forest in Hubei Province show that the load values of the average DBH,average tree height,arbor volume per hectare and age group are larger in the first principal component of timber and energy forest evaluation index,which reflects the growth status of trees.The load values of the community structure integrity and shrub coverage in the second principal component are larger,which reflects the structural characteristics of the forest stand.The load values of herb coverage,slope position and traffic location grade are larger than those of other factors in the third principal component,which mainly reflects the site conditions of the forest stand.The load values of soil thickness and humus thickness are larger in the fourth principal component,which reflects the soil fertility of the forest stand.The load values of the number of trees per hectare and canopy density in the fifth principal component are larger,which reflects the density characteristics of the forest stand.The load values of shrub coverage,economic forest production period,average age,total vegetation coverage and number of trees per hectare are larger in the first principal component of economic forest evaluation index,which mainly reflects the tree growth and stand status.The load value of slope grade in the second principal component is larger,which reflects the site condition of the forest stand.The load values of herbaceous coverage and total vegetation coverage are larger in the third principal component,which reflects the vertical structure of the forest stand.The load values of humus thickness and soil thickness are larger in the fourth principal component,which reflects he soil fertility of the forest stand.The load value of the number of plants per hectare in the fifth principal component is larger,which reflects the density characteristics of the forest stand.Based on the comprehensive quality and efficiency evaluation results and the key indicators of improving quality and efficiency,the artificial commercial forest can be divided into five low-quality and low-efficiency types:poor tree growth,poor community structure,poor site condition,poor soil fertility and unreasonable stand density.(5)The comprehensive quality and efficiency evaluation of the typical management models for improving the quality and efficiency of artificial commercial forest in Hubei Province shows that the comprehensive quality-efficiency index of typical timber forest management models are ranked from high to low as follows:Poplar-Mustard and Poplar-Broccoli>Poplar-Corn>Poplar-Wheat and Poplar-Rape>young poplar pure forest in young poplar forest models,Poplar-Raising>pure poplar forest in the middle-aged poplar forest models,the Variety of Precious Tree Species Transformation Model>Masson pine-Phoebe zhennan>Masson pine Forest breeding-Hunting Model>Masson pine-Buerger maple>Close-to-nature Management Model>Masson pine-Camellia oleifera>Masson pine-Camellia japonica>masson pine pure forest in the masson pine forest models,the Variety of Precious Tree Species Transformation Model>Chinese fir-Phoebe zhennan>Chinese fir-Rhododendron simsii>Chinese fir-Chinese sweetgum>Chinese fir pure forest in the Chinese fir forest models.The comprehensive quality-efficiency index of typical economic forest management models are ranked from high to low as follows:Walnut-Green Seedlings>Walnut-Raising>Walnut-Mixed Seedlings>Walnut-Ginkgo Seedlings>Walnut-Loquat Seedlings>walnut pure forest in the walnut forest models,Sparse Citrus>Citrus-Sweet potato>Citrus-Sesame and Citrus-Peanut>Densely Planted Citrus in the citrus orchard models,Tea-Corn>Tea-Chinese fir and Tea-Pear>Tea-Castanea mollissima>Tea-Paulownia fortunei>Densely Planted Pure Tea Plantation in the tea plantation models,Castanea mollissima-Belamcanda chinensis>Castanea mollissima-Atractylodes lancea>Castanea mollissima-Rape>Castanea mollissima-Polygonatum sibiricum>Castanea mollissima-Pasture-Breeding Compound Model>Castanea mollissima-Camelliasinensis>the Chestnut Forest Transformation model>Castanea mollissima-Hemerocallis>high-density pure chestnut forest in the chestnut forest models.It can be seen that these management models have the effect of improving quality and efficiency.The average increase of the comprehensive quality-efficiency index of the typical management models of timber forest for improving quality and efficiency relative to pure forest is 14.13%,and the average increase of masson pine forest is the largest(17.34%),followed by Chinese fir forest(17.04%),poplar forest is the smallest(8.44%),indicating that the overall effect of the typical management models of masson pine forest is the best.The average increase of the comprehensive quality-efficiency index of the typical management models of economic forest is 14.13%,and the average increase of walnut forest is the largest(11.98%),chestnut forest is the second(10.98%),tea plantation is the third(9.46%),citrus orchard is the smallest(3.83%),indicating that the overall effect of the typical management models of walnut forest is the best,but the effect of citrus orchard is not obvious.(6)According to the characteristics of the typical management model of artificial commercial forest in Hubei Province with significant improvement in quality and efficiency,as well as the differences in under-forest planting and breeding species and management measures,it can be divided into seven types.The Forest-Grain(Oil-bearing crops)model can significantly promote the average DBH and average tree height growth of timber forests,increase forest stand accumulation,increase the social and economic benefits of economic forests,increase the economic benefits of farmers to a certain extent,and alleviate the contradiction of agricultural and forestry land competition under the returning the grain plots to forestry policy.The Forest-Nursery stock(Flowers)model can increase the shrub coverage,improve the stand structure,increase the forest stand stability,maximize the social and economic benefits of timber forest,significantly increase employment opportunities of economic forests,and relatively improve the income of economic forests.The Forest-Vegetable model can increase herb coverage,greatly improve the humus thickness and soil fertility by fertilization,effectively promote the growth of the average DBH and the average tree height of the timber forest,and significantly increase the income and employment opportunities of the economic forest.The Forest-Officinal model can support long-term forestry development through short-term planting officinal,and it can not only greatly increase the income and employment opportunities of economic forest,but also increase herb coverage and humus thickness to a certain extent.The Forest-Tea model can significantly increase the shrub coverage,humus thickness and soil thickness of timber forest and economic forest,thereby reducing soil erosion,improving site conditions,and increasing ecological benefits.The Forest-Breeding Compound model can raise poultry and livestock in various types of woodlands without site conditions,increase humus thickness of timber forest and economic forest to a certain extent and significantly increase the herb coverage of economic forest by planting forage.The Thinning and Replanting Transformation model can effectively improve the canopy closure of timber forest,reasonably adjust the density of timber forest and economic forest,and increase the stability of the community.(7)According to the objectives and characteristics of the management model types,suitable management models and key technologies for improving the quality and efficiency of various low-quality and low-efficiency artificial commercial forest types in Hubei Province are proposed.(1)The suitable models for low-quality and low-efficiency artificial commercial forest with poor tree growth are the Forest-Grain(Oil-bearing crops)model and the Forest-Vegetable model.The key management techniques of the Forest-Grain(Oil-bearing crops)model include measures such as reasonable deep tillage,fertilization,crop rotation and adjustment of tree row spacing,so that forest trees and crops can grow together and promote each other,etc.The key management techniques of the Forest-Vegetable model include the rational selection of vegetable varieties to be planted according to the under-forest light intensity and its seasonal changes,etc.(2)The suitable model for the low-quality and low-efficiency artificial commercial forest with poor community structure is the Forest-Nursery stock(Flowers)model.The key management techniques include selecting suitable slow-growing nursery stock species according to the market demand and the principle of adapting to the site and the tree,etc.(3)The suitable models for the low-quality and low-efficiency artificial commercial forest with poor site condition are the Forest-Tea model and the Forest-Breeding Compound model.The key management techniques of the Forest-Tea model include reasonable slope conversion to terraces,control of the spacing of forest trees and the spacing of tea beds,etc.The key management techniques of the Forest-Breeding Compound model include reasonable control of the density of stocking poultry and livestock to prevent environmental pollution,etc.(4)The suitable model for low-quality and low-efficiency artificial commercial forest with poor soil fertility is the Forest-Officinal model.The key management techniques include determining planting varieties and areas according to market demand,and improving the soil to adapt to the growth of different medicinal materials,etc.(5)The suitable model for low-quality and low-efficiency of artificial commercial forest with unreasonable stand density is the Thinning and Replanting Transformation model for thinning and replanting.The key management techniques include reasonable control of the intensity of thinning,and replanting in accordance with the principle of adapting to the site and the tree,etc. |
