Effects of Cutting Intensity on Soil Physical and Chemical Properties in a Mixed Natural Forest in Southeastern China

Abstract

Abstract:The mixed Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.), Masson's pine (Pinus massoniana Lamb.), and hardwood forest is a major forest type in China and of national and international importance in terms of its provision of both timber and ecosystem services. However, over-harvesting has threatened its long-term productivity and sustainability. We examined the impacts of timber harvesting intensity on soil physical and chemical properties 10 and 15 years after cutting using the research plots established with a randomized block design. We considered five treatments, including clear cutting and low (13.0% removal of growing stock volume), medium (29.1%), high (45.8%), and extra-high (67.1) intensities of selective cutting with non-cutting as the control. The impact on overall soil properties derived from principal component analysis showed increasing with a rise in cutting intensity, and the most critical impact was on soil nutrients, P and K in particular. Soil nutrient loss associated with timber harvesting even at a low cutting intensity could lead to nutrient deficits in this forest although most of the soil physical properties could be recovered under the low and medium intensities of cutting. These results indicate that clear cutting and the selective cutting of extra-high and high intensities should be avoided in this type of forest in the region.

Effects of Thinning on Soil Organic Carbon Fractions and Soil Properties in Cunninghamia lanceolata Stands in Eastern China

“…Most of these studies, however, mainly focus on the short-term effects of thinning on soil properties. In contrast, much less is known about the effects of repeated thinnings on soil properties, over a longer time period [3].…”

“…Numerous studies have shown that soil physical properties, such as bulk density and soil hydraulic parameters, change with depth, following thinning [3,[57][58][59]. However, most of these studies focused on the short-term impact of one thinning operation, on soil physical properties.…”

“…Some studies have shown that thinning deteriorates soil properties, which leads to an increase in soil bulk density, a reduction in soil water holding capacity and porosity in a mixed natural forest in southeastern China [3], and a decrease of nitrogen, phosphorus, and potassium in a mixed plantation in northeastern China [24] and a Mediterranean forest in southeastern Spain [8]. Other studies have found that thinning has little effect on soil physical and chemical properties at Coram Experimental Forest in northwestern Montana [25].…”

“…Forest management practices might affect the stability and size of soil organic carbon (SOC) pools, as well as the soil properties, by changing environmental conditions and vegetative production [1][2][3]. Thinning is a general silvicultural practice.…”

“…It alters the micro-environment within modified stands, temporarily enhancing soil nutrient availability and altering soil moisture, soil temperature, root distribution, and the microbial community [4,5]. Soil physical and chemical properties are influenced by the changes of stand environment, which correlates with thinning intensity, interval, and method [3,6]. The variations in soil properties after thinning have the potential to greatly impact the tree growth [3,7], site productivity [7], and soil carbon sequestration [8,9].…”