桂東引種香合歡造林成效初報

莫宗明 譚長強 方小玉 李偉彬

摘 要 為調整森林樹種結構，提高森林質量和綜合效益，廣西東部的國有大桂山林場從桂西北天然分布區(qū)引種香合歡（Albizia odoratissima）。對其4 年生引種林分進行了調查，結果表明：香合歡具有較好的適應性，林木保存率達到95.3%，平均樹高4.19 m，平均胸徑4.6 cm，平均冠幅2.36 m，郁閉度0.5，樹高和胸徑均呈正態(tài)分布，主干通直和較通直的林木比例高達77.4%，林木沒有遭受中度及以上林業(yè)有害生物為害，適宜培育用材林。

關鍵詞 林木引種；人工造林；造林成效；香合歡

中圖分類號：S725.1?????? 文獻標識碼：A?? doi：10.13601/j.issn.1005-5215.2024.04.012

Preliminary Report on the Afforestation Effect of Albizia odoratissima Introduced to the East of Guangxi

Mo Zongming1，Tan Changqiang2，F(xiàn)ang Xiaoyu3，Li Weibin4

（1. State-owned Daguishan Forest Farm of Guangxi Zhuang Autonomous Region，Hezhou 542899，China; 2. Institute of Forestry Sciences of Guangxi Zhuang Autonomous Region，Nanning 530002，China; 3. Center for Rescue Research of Terrestrial Wildlife and Monitoring of Epidemic Diseases in Guangxi Zhuang Autonomous Region，Nanning 530028，China; 4. Nanning Wildlife Conservation Station of Guangxi Zhuang Autonomous Region，Nanning 530022，China）

Abstract In order to adjust the structure of forest species and improve forest quality and comprehensive benefits，the State-owned Daguishan Forest Farm located in the east of Guangxi introduced Albizia odoratissima from its natural distribution area in the northwest of Guangxi. The four-year-old introduced forest stands were investigated. The results showed that Albizia odoratissima had good adaptability，the preservation rate of trees reached 95.3%，the average tree height was 4.19 m，the average DBH was 4.6 cm，the average crown width was 2.36 m，and the canopy density was 0.5. The tree height and DBH showed normal distribution，and the proportion of straight and straighter trunk trees was as high as 77.4%. The trees were not damaged by moderate and above forestry pests，and were suitable for cultivating timber forests.

Key words forest tree introduction; artificial afforestation; afforestation effect; Albizia odoratissima

香合歡（Albizia odoratissima）又名土格木、黑格、鐵掖蒿、香須樹等，是豆科（Leguminosae）合歡屬落葉喬木，列入《主要栽培珍貴樹種參考名錄（2022年）》，在廣西壯族自治區(qū)主要天然分布于桂西北[1]，根系發(fā)達，萌芽力強，耐貧瘠、耐干旱，具有根瘤固氮作用[2]，能改良土壤和保持水土。其木材堅硬[3]，紋理致密，心材顏色較深，多呈巧克力色、褐色，抗蟲耐腐，不容易開裂和變形，是家具、木地板、建筑等優(yōu)質用材，具有極高的經(jīng)濟價值。冠形良好，具有較高的園林觀賞價值。

廣西國有大桂山林場位于廣西東部，部分林地由于長時間營造單一樹種桉樹（Eucalyptus spp.），林地土壤出現(xiàn)輕度退化，土壤有機質、全氮、銨態(tài)氮、硝態(tài)氮、全鉀、速效鉀等多種養(yǎng)分含量均不同程度下降[4]，養(yǎng)分供應不平衡，桉樹生長不良，單位面積木材產(chǎn)量低，森林生態(tài)系統(tǒng)穩(wěn)定性不高。因此，適當引種香合歡等高價值珍貴樹種，合理調整森林樹種結構，充分發(fā)揮森林生態(tài)效益、經(jīng)濟效益、社會效益等多功能效益，對促進森林可持續(xù)經(jīng)營和助力鄉(xiāng)村振興具有重要意義。

1 材料與方法

1.1 材料

1.1.1 試驗地概況 香合歡引種造林試驗地位于廣西壯族自治區(qū)東部的賀州市八步區(qū)國有大桂山林場六排分場，111°41′54″E， 24°8′21″N，海拔245 m。地處南亞熱帶季風氣候區(qū)，年平均氣溫19.7? ℃，7月份平均氣溫30? ℃，1月份平均氣溫14? ℃；無霜期300 d，冬暖夏涼，年平均日照時數(shù)1 751 h；年平均降水量1 551 mm，降雨主要集中在5—8月，雨熱同季。林地成土母巖為砂頁巖，土壤類型為赤紅壤，土層厚度45 cm，土壤pH為5.5。造林前林地類型為桉樹商品林采伐跡地。