Growth and carbon sequestration of poplar plantations on the Tibetan Plateau. (March 2023)

• Record Type: Journal Article
• Authors: Yao, Yuan; Shu, Shumiao; Wang, Wenzhi; Liu, Ruixuan; Wang, Yuelin; Wang, Xiaodan; Zhang, Sheng
• Is Part Of: Ecological indicators. Volume 147(2023)
• Publication Date: 2023-03
• Subjects: b metabolic exponent -- d forest density -- D average f(m) -- DBH diameter at breast height -- D/T organism/tree mean growth rate -- f(m) the total biomass of new tissue created during the formation time -- f(m)/T the growth rate -- o the initial biomass -- f(r) the increment in r during time T -- gr cost of respiration needed to produce a unit of tissue -- HPA high altitude of PA plantations -- HPB high altitude of PB plantations -- IGM iterative growth model -- IGMF IGM expansion at the forest scale -- IGMF-L the thermodynamic lower boundaries of forest NPP -- IGMF-U the thermodynamic upper boundaries of forest NPP -- IGMR tree-ring iterative growth model -- IGMR-L the thermodynamic lower boundaries of tree ring growth -- IGMR-U the thermodynamic upper boundaries of tree ring growth -- LPA low altitude of PA plantations -- LPB low altitude of PB plantations -- m organism/tree current size -- M organism/tree potential maximum size -- mr rate of maintenance respiration per unit of tissue -- MPA middle altitude of PA plantations -- MPB middle altitude of PB plantations -- NPP net primary productivity -- PA Populus alba L -- PB Populus × beijingensis -- r current tree DBH -- r0 the initial DBH -- R the maximum DBH -- T, formation time of unit tissue which is primarily controlled genetically and by physiological activities, with the intrinsic or developmental growth rate independent of organism size -- X forest current biomass -- Xmax forest potential maximum biomass; Populus -- Iterative growth model -- Tree ring -- Low-frequency growth signals -- Yarlung Tsangpo River; Environmental monitoring -- Periodicals; Environmental management -- Periodicals; Environmental impact analysis -- Periodicals; Environmental risk assessment -- Periodicals; Sustainable development -- Periodicals; 333.71405
• DOI: 10.1016/j.ecolind.2023.109930
• Languages: English
• ISSNs: 1470-160X

Abstract

Graphical abstract: Highlights: The intrinsic growth trend of trees follows a unimodal pattern and changes overall with climate. Poplars adapt to plateau climate by reducing growth rates and increasing longevity. Populus × beijingensis is a more suitable poplar species on the Tibetan Plateau. Abstract: Tree radial growth has long-term adaptation and rapid responses to climate, manifested as age-dependent low-frequency and climate-sensitive high-frequency signals. Although the former is usually removed in climate-growth analyses, its overall change still profoundly affects forest biomass and carbon sequestration. The iterative growth model (IGM) reveals the underlying links among organism lifespan, growth rate, and respiration, providing a set of theoretical indicators to evaluate or predict growth. Here, IGM was extended to the tree-ring scale (IGMR) to study the low-frequency growth signals of poplar plantations in the Yarlung Tsangpo River, Tibetan Plateau. As predicted by the IGMR, the low-frequency growth signals all follow a unimodal pattern over the diameter at breast height (DBH) gradient while constraining the high-frequency signals. The unimodal growth curves' length (maximum DBH), height (maximum growth rate of tree DBH), and resulting tree lifespan could be used to assess and predict tree growth. The results showed that the maximum DBH, growth rate and inverse of the longevity of the trees were greater at lower elevations. The indicators of Populus × beijingensis (PB) were better than those of P. alba (PA). Overall, poplars adapted to the plateau climate by reducing growth rates and increasing longevity. Temperature was the key factor affecting these trade-offs, with the best temperature at 14.69 ℃. Combined with stand density, PB plantations (11695.58 ± 1704.98 g/m 2 ) had greater potential maximum biomass than PA plantations (9032.50 ± 2031.21 g/m 2 ). This study highlights that the response of low-frequency growth signals to environments is holistic, and the resulting indicators have important value for evaluating and predicting tree growth and forest carbon sequestration. Moreover, the results have important practical significance for reasonable plantations and proper assessment of the ecological contribution of plantation forests on the Tibetan Plateau.