摘要
树龄是树木的重要生长特征。但对于像杜鹃这样的灌木来说,多数茎秆难以使用普通生长锥进行采样观察。利用植物径向生长与树龄之间存在的相关关系,建立经验回归方程,由基径估算年龄是一个简单有效的方法。在湖北罗田的黄狮寨随机选择了12个大小不一的杜鹃的主茎,测量其基径,截取茎秆的圆盘样品观察年轮,得到样本个体的基径在8.44~48.21 mm之间,年轮数在6~53 a之间。用直线回归、指数回归、幂函数回归三种方法分别建立了年轮数与其基径的经验方程,结果发现,三个回归方程都是极显著的,直线回归方程估计杜鹃平均年轮宽度为0.615 3 mm/a。指数函数方程的决定系数最大,表明在所调查的树龄范围内,杜鹃径向生长速度更符合指数增长规律,呈前期慢、后期加快的特点。使用该指数回归方程估计年轮数的平均偏差为3.044 6 a,最大偏差小于12 a,采用指数回归方程可以估算出本地杜鹃树龄的大致年代,推测本地杜鹃居群主要是在五十多年前开始定居繁殖的。
Tree age is an important growth feature of trees. But for shrubs like Rhododendron simsii,most stems are difficult to sample using ordinary growth cones. Using the correlation between plant radial growth and tree age,establishing empirical regression equations about age and stem diameter was a simple and effective method for age estimating. In the Huangshizhai of Luotian,Hubei,12 main stems of different sizes of rhododendron were randomly selected,and the base diameter was measured,the circle samples of the stems were taken to observe the annual rings,and the base diameter of the sample individuals was 8.44~48.21 mm. The number of annual rings is between 6~53 a. Three regression models,linear,exponential,power functional,were established,all of them were significant statistically(P<0.01) and can be used to estimate ages for the population. Estimated by linear regression model,the average width of the annual rings was about 0.615 3 mm/a. The R^2 of the exponential model was maximum among the three models,indicating that,in the range surveyed,the radial growth rate was more in line with the exponential growth law,slow at began and accelerate at later. The average deviation between estimates from the exponential model and observes for annual rings was about 3.044 6 a,the maximum deviation less than 12 a,the exponential regression equation can be used to estimate ages in units of about ten years. It was speculated that the local Rhododendron simsii population began to settle and reproduce more than 50 years ago.
作者
金卫斌
李志良
王书珍
陈海林
Jin Weibin;Li Zhiliang;Wang Shuzhen;Chen Hailin(College of Biology and Agricultural Resource,Huanggang Normol University,Huanggang 438000)
出处
《湖北林业科技》
2019年第6期4-5,8,共3页
Hubei Forestry Science and Technology
基金
国家自然科学基金(31500995)
关键词
杜鹃
树龄
基径
回归方程
Rhododendron simsii
tree age
base diameter
regr
