Robinia Pseudoacacia Plantations Research Articles

Predicting soil respiration using carbon stock in roots, litter and soil organic matter in forests of Loess Plateau in China

Understanding the dominant variables driving soil respiration is critically important for predicting soil CO2 emission and assessing the carbon balance of forest ecosystems. In a small catchment of the semiarid Loess Plateau in China, soil respiration and soil biophysical factors were studied on sites of five forest types, comprising plots established in a pure Pinus tabulaeformis plantation, a pure Robinia pseudoacacia plantation, a mixed P. tabulaeformis and R. pseudoacacia plantation, a pure Platycladus orientalis plantation, and a natural Populus davidiana stand. Soil temperature at the 10 cm depth was found to be the most predominant factor controlling the temporal pattern of soil respiration, accounting for 11–40% seasonal variation in the rate of soil CO2 efflux across forest types. By applying an empirical model and the calculated temperature sensitivity of soil respiration (Q10) and the rate of basal soil respiration (R10), annual soil CO2 emission was estimated separately for each forest type using the automatically monitored data of soil temperature at the 10 cm depth. The annual soil CO2 emission varied greatly with forest types and ranged from 647.71 g C m−2 y−1 in the P. orientalis plantation to 1448.50 g C m−2 y−1 in the natural P. davidiana stand. Annual soil CO2 efflux is better predicted by soil organic carbon content and the amount of carbon in roots, litter and top soil than soil temperature when data are pooled for all plots of the five forest types. A first order exponential analysis indicates that about 77% of the variation in annual soil CO2 efflux is explained by root carbon stock, 63% by the combined carbon stock in roots, litter, and top soil, and 48% by the combined carbon stock in litter and top soil. We conclude that annual soil CO2 efflux can be predicted by carbon pools in roots and soils rather than by soil temperature in watersheds where spatial variation in soil temperature is relatively small in the semiarid Loess Plateau of China.

Basic soil properties and comprehensive evaluation in different plantations in rocky desertification sites of the karst region of Guizhou Province, China

Aims Soil quality plays an essential role in vegetation restoration in the karst soil ecosystem.Many studies have reported soil quality of different plantations and vegetation successional stages in karst regions,but few have focused on the seasonal dynamics of basic soil properties.Our objectives were to investigate annual dynamics of basic soil properties of different types of plantations and evaluate soil integrated quality index(SQI).Methods We analyzed the dynamics of soil physical and chemical properties and soil enzyme activities for four sites in Puding County,Guizhou Province,China:Robinia pseudoacacia plantation(RP),Cupressus duclouxiana plantation(CD),R.pseudoacacia-C.duclouxiana mixed plantation(RD) and a non-plantation area(CK).Soil samples were collected in alternate months from September 2009 to September 2010.Soil factors were measured using general methods,and data were analyzed using SPSS 13.0 software.Important findings Soil physical properties of all three plantations had an advantage over the non-plantation area and were slightly improved within one year.There were significant differences in soil nutrients and soil pH among the four sites(p 0.01).Soil urease activity in all sites was highest in September and lowest in January.Soil invertase activities were remarkably different among the four sites(p 0.01).Soil catalase activity exhibited a unimodal peak,and alkaline phosphatase activity had a bimodal peak.Soil polyphenoloxidase activity was lowest in January and very low in RP throughout the study.Moreover,the rank of means of five soil enzyme activities was different among the four sites.The SQI of RP,CD,RD and CK was 0.748,0.406,0.590 and 0.315,respectively.In general,all three types of plantations,but especially RP and RD,could improve soil quality after conversion of farmland to forest.

Correlation of eco-hydrographic benefit and height increment of Robinia pseudoacacia stand with climatic environmental factors in Yellow River Delta Wetland of China

The relationship between eco-hydrographic benefit of forest vegetation and climatic environmental factors is one of the focuses in the research on environmental protection and ecosystem countermeasures in Wetland. The runoff, sediment and soil moisture rate dynamics in Robinia pseudoacacia plantation and its clearcut area were investigated in the natural runoff experiment plots in Yellow River Delta Wet-land, Shandong Province, China. The correlation of height increment of R. pseudoacacia stand was 25 min later than in its clerarcut area. The soil moisture rates in R. pseudoacacia stand and its clearcut varied periodically with annual rainfall precipitation in both dry season and humid season. The annual mean soil moisture rate in R. pseudoacacia stand was 23.3%-25.6% higher than that in its clearcut area. Meanwhile, a regression model reflecting the correlation between the height increment of R. pseudoacacia and climatic factors was developed by stepwise regression procedure method. It showed that the light was the most important factor for the height increment of R. pseudoacacia, followed by water and heat factors.

A model for vertical distribution of fine roots in Robinia pseudoacacia plantations on the Loess Plateau

Based on a detailed investigation of vertical distributions of fine roots in Robinia pseudoacacia plantations at the Ansai Soil and Water Conservation Station, Shaanxi Province, a model was developed for the deep distribution of fine roots of R. pseudoacacia, which reflects the growth of fine roots affected by the mixed process of infiltration water and deep soil water. The maximum depth of the distribution h max and the depth of the highest fine root density (FRD) h p were determined and the maximum depth of infiltration water supplied for fine root growth h q could also be calculated, h q was considered as the approximate boundary between infiltration water and deep soil water in support of the growth of fine roots. According to the model, the soil water of R. pseudoacacia woodland in the profile could be classified into three layers: the first layer from the soil surface to h p was the active water exchange layer, very much affected by precipitation; the second was the soil water attenuation layer, between h p and h q and largely affected by the vertical distribution of fine roots; the third was the relatively stable soil water layer below h q, below which soil water did not change much. The percentage of infiltration water supplied for the growth of fine roots reached a level of 88.32% on the shaded slopes and 85.21% on sunny slopes. This indicated infiltration of precipitation played a crucial role in the growth of R. pseudoacacia in the gully region of the Loess Plateau. The research of interaction between the distribution of fine roots and soil water in the profile will help to explain the reasons for the complete drying out of soils and provide a theoretical basis for continuing the policy of matching tree species with sites on the Loess Plateau.

Vegetation Management Units and Its Landscape Structures of Mt. Cheolma, in Incheon City, Korea

For landscape ecological management of the isolated forestlands in Incheon city located in the western tip of South Korea, the forest vegetation of Mt. Cheolma was classified phytosciologically and mapped out its spatial distribution at a scale of 1:5,000. Characteristics of forest landscape structures were discussed in terms of the number and size of patches obtained by analy zing vegetation map. Units to manage the forest vegetation were categorized into eighteen communities, seventeen groups, and sixteen subgroups. Landscape elements were classified into five types: secondary vegetation, introduced vegetation for forestry (IVF), introduced vegetation for agriculture (IVA), and other elements. Two hundred and ninety-three forest landscape patches covers 443.3ha, of which IVF accounted for 316.8ha(71.5), the largest portion, secondary vegetation for 101.2ha(22.8), IVA for 6.2ha(1.4), and others for 19.1ha(4.3). The ratio of natural forest elements of 31.9 showed that this area was mainly comprised of artificially introduced vegetation, such as Robinia pseudoacacia plantation and Pinus rigida plantation. Forest landscape patches have a mean area of 4.5ha, a density of 66.1/100ha, and a diversity index of 0.87. It was estimated that differentiation of patches recognized in community level would be related to human interference and those in subordinate level to natural processes.