Growth responses of broad-leaf and Korean pine mixed forests at different successional stages to climate change in the Shengshan Nature Reserve of Heilongjiang Province, China

Abstract

Aims This research examined the different response of tree growth to climate change at the early, middle, late and matured successional stages of Korean pine (Pinus koraiensis) and broadleaf mixed forest. Methods This research used dendroecological methods to analyze radial growth at different successional stages of Korean pine forests in response to climatic change in the Shengshan Nature Reserve of Heilongjiang. Important findings Chronology statistics indicated that the sensitivity of radial growth to inter-annual climate variability decreased from early to later successional stage. Meanwhile, the influence of some climate indices to radial growth also changed during the successional process. Radial growth of matured forest was positively related to mean monthly temperature in June and December of previous year, revealing an obvious "lag effect" of temperature. The ring-width of matured forest had a negative correlation with mean monthly temperature but a positive correlation with monthly precipitation in June of current year, reflecting the limiting role of growing season water availability. However, these limiting effects gradually disappeared towards the earlier stages of forest succession. On the contrary, the growth of early successional forest was negatively correlated to precipitation in June of previous year, and this effect disappeared towards the later successional stages. These differences revealed increased demand of water by dominant species from early to later successional stages. A moving correlation analysis showed that the increased warming and drying climate in the research area had both positive and negative influences on radial growth of each forest type. Earlier successional forests did not show clear long-term growth

Forest type and height are important in shaping the altitudinal change of radial growth response to climate change

“…For instance, Liang et al . 18 found that MS and SD decrease from early- to late-successional forests in a same site in northeast China. These results suggest that species identity may be another important factor affecting MS and SD in addition to environmental condition.…”

“…Similarly, on an arid mountain in northwest China, MS and SD decreased while tree height increased with higher altitude 27 . In another study along a successional series, MS and SD decreased from early- to late-successional forests, accompanied by an increase in forest height towards late-successional forests 18 . Nevertheless, the potential role of forest height was not explored in these studies.…”

“…ref. 55 ), and forest height also increases towards late-successional forests 18,41 . According to our hypothesis, MS and SD should be lower in later-successional forests, and thus lead to a negative relationship of MS and SD with forest height.…”

“…This is similar to the latitudinal gradient and thus more useful in understanding the different growth response to climate change at broad scales. Other studies have found that different forest types (species) under a similar climate may show contrasting growth response to climate change, suggesting that species identity is another key factor leading to different growth response 4,11,17,18 . Thus, different forest types distributed along elevational gradients may contribute to the altitudinal change of RWI-climate relationship, but its relative effect vs. climate gradient has not been well quantified.…”

Tree-ring widths are good proxies of annual variation in forest productivity in temperate forests

“…This is because the growth and mortality of large trees are more sensitive to water deficit than smaller trees as a result of their high stature (which lead to greater difficulty in vertical water transportation to canopy). Northeast China has experienced the most drastic climate warming in China and the related drought trends is also evident in the past decades 36 , which have showed clear negative impacts on forest growth 37 . Our results suggest the need for further examining the role of large trees in forest dynamics, and the conservation of large trees in response to climate change.…”