[Research progress on cambium activity and radial growth dynamics monitoring of coniferous species]. / é’ˆå¶æ ‘å½¢æˆå±‚æ´»åŠ¨åŠå¾„å‘ç”Ÿé•¿ç›‘æµ‹ç ”ç©¶è¿›å±•.

The radial growth of trees plays a crucial role in determining forest carbon sequestration capacity. Understanding the growth dynamics of trees and their response to environmental factors is essential for predicting forest's carbon sink potential under future climate change. Coniferous forest trees are particularly sensitive to climate change, with growth dynamics responding rapidly to environmental shifts. We collected and analyzed data from 99 papers published between 1975 and 2023, and examined the effects of exogenous factors (such as temperature, water, and photoperiod) and endogenous factors (including tree age and species) on cambial activity and radial growth in conifers. We further explored the mechanisms underlying these effects. The results showed that climate warming had the potential to advance the onset while delayed the end of xylem differentiation stages in conifers in temperate and boreal regions. Water availability played a crucial role in regulating the timing of cambial phenology and wood formation by influencing water potential and cell turgor. Additionally, the photoperiod not only participated in regulating the start and end times of growth, but also influenced the timing of maximum growth rate occurrence. Future climate warming was expected to extend the growing season, leading to increase in growth of conifers in boreal regions and expanding forests to higher altitudes or latitudes. However, changes in precipitation patterns and increased evapotranspiration resulting from temperature increases might advance the end of growing season and reduce growth rate in arid areas. To gain a more comprehensive understanding of the relationship between radial growth and climatic factors, it is necessary to develop process-based models to elucidate the physiological mechanisms underlying wood formation and the response of trees to climatic factors.

[Stem radial growth of Picea crassifolia in response to climatic factors in the western Qilian Mountains, China]. / ç¥è¿žå±±è¥¿éƒ¨é’æµ·äº‘æ‰å¾„å‘ç”Ÿé•¿å¯¹æ°”å€™å› å­çš„å“åº”.

The radial growth of eight individuals of Picea crassifolia and environmental factors were monitored by Dendrometer and automatic meteorological station in the western Qilian Mountains. The Gompertz function fitted results showed that the radial growth of P. crassifolia started on April 19, April 17, and April 10 in 2018, 2019 and 2020, respectively, and that the radial growth started when daily mean temperature exceeded 5.5 ℃. The radial growth of P. crassifolia ended on August 17, August 21, and July 19 in the three years, respectively. The ending time of radial growth was related to precipitation at the end of growing season. The radial growth of P. crassifolia was strongly inhibited by drought, and it had the strongest correlation with daily mean temperature (negative correlation) and daily precipitation (positive correlation) in July. The correlation of radial growth with the daily precipitation in the early growing season (May) showed significant inter-annual variation.

[Research progress on cambial activity of trees and the influencing factors]. / æ ‘æœ¨å½¢æˆå±‚æ´»åŠ¨åŠå ¶å½±å“å› ç´ ç ”ç©¶è¿›å±•.

Tree growth is the main way of carbon sequestration in forest ecosystems, which is influenced by climatic and non-climatic factors. The long-term location monitoring of cambial phenology and wood formation dynamics (xylogenesis) is an important method to clarify the responses of radial growth to climate change. Here, we reviewed studies on cambial phenology and xylogenesis by microcoring method. Firstly, we reviewed the effects of climatic factors on cambial phenology. The onset and cessation of xylogenesis were determined by temperature in cold and humid conditions. Temperature and water availability collectively modulated the onset of xylogenesis under dry conditions, and the later determined the end of xylogenesis. The radial increment was regulated by rate and duration of cell production, with the maximum of growth rate occurring around the summer solstice. Short-term N addition did not affect wood formation dynamics. Secondly, we reviewed the roles of biological factors in regulating xylogenesis. The onset of xylogenesis differred among species, ages, and inter-specific competition. Seasonal dynamics of non-structural carbohydrates were coupled with wood formation. Finally, we reviewed the response mechanisms of xylogenesis to the interaction of climatic and biological factors. In conclusion, we put forward problems in current studies and prospected future development to provide reference for further scientific research.