图  3  基于两种重要性度量方法的各自变量对单木胸径年平均生长量影响的相对重要性得分

TreeSpe_Code: 树种代码 Tree species code; Amaxt: 年最高气温 Maximum annual temperature; Amint: 年最低气温Minimum annual temperature; Amt: 年平均气温Mean annual temperature; Gsdd5: 生长季大于 5 ℃积温 (4—9月) The accumulated temperature is greater than 5 ℃ in growing season (April to September); Gsmaxt: 生长季最高气温 (4—9月) Maximum temperature in growing season (April to September); Gsmint: 生长季最低气温 (4—9月) Minimum temperature in growing season (April to September); Maxtwm: 最热月的最高气温 (7月) The highest temperature in the hottest month (July); Mmincm: 最冷月的最低气温 (1月) The lowest temperature of the coldest month (January); Mtcm: 最冷月的平均气温(1月) The mean temperature of the coldest month (January); Mtwm: 最热月的平均气温(7月) The mean temperature of the hottest month (July); Gsp: 生长季平均降水量(4—9月) Average precipitation in growing season (April to September); Map: 年均降水量 Mean annual precipitation; Msp: 月总降水量Monthly total precipitation; Sp: 夏季降水量(6—8月) Summer precipitation (June to August); Gsrh: 生长季相对湿度 (4—9月) Relative humidity in growing season (April to September); Marh: 年平均相对湿度 Annual mean relative humidity; Asr: 年总太阳辐射时长Annual total solar radiation duration; Gssr: 生长季太阳辐射时长 (4—9月) Solar radiation duration in growing season (April to September); Ahm: 1 000 × ((Amt + 10)/Map); Shm: Gsmaxt + Maxtwm; Amaxtmap: Amaxt/Map; Amtmap: Amt/Map; Gsmaxtgsrh: (Gsmaxt × Gsrh)/1 000; Gsmintgsp: Gsmint/Gsp; Gsmintgsrh: Gsmint/Gsrh; Gsmintmap: Gsmint/Map; Gspdd5: (Gsp × Gsdd5)/1 000; Gspgsrh: Gsp/Gsrh; Gspmtcm: (Gsp × Mtcm)/1 000; Gspgsmint: (Gsp × Gsmint)/1 000; Gsrhgsmint: (Gsrh × Gsmint)/1 000; Mapdd5: (Map × Gsdd5)/1 000; Mapgsmint: (Map × Gsmint)/1 000; Mapmtcm: (Map × Mtcm)/1 000; Maxtwmsp: Maxtwm/Sp; Mtcmgsp: Mtcm/Gsp; Mtcmmap: Mtcm/Map; Pratio: Gsp/Map.

Figure  3.  Relative importance scores of each independent variable affecting individual tree DBH growth based on two methods of variable importance calculation