Survival, Growth and Soil Drivers of Four‐Year‐Old Mulanje Cedar Provenances in Malawi

Widdringtonia whytei (Mulanje cedar), Malawi’s critically endangered national tree, has declined > 80% since the 1950s from overharvesting, fires and regeneration failure. Previous reforestation initiatives have yielded inconsistent establishment success, attributable to inadequate genotype × environment matching and insufficient edaphic characterization, necessitating empirical research to inform restoration under intensifying climate pressures. This study evaluated 4‐year field performance including survival, root collar diameter (RCD) and height of three provenances (Zomba, Chikangawa and Tanzania) established across five operational high‐altitude sites in Malawi (Thuchira, Zomba Plateau, Dedza Mountain, Luwawa and Chikangawa). Trials followed randomized complete block designs using a randomized complete block design with five blocks per site and 7 × 7 tree plots assessed on a 5 × 5 core. Site conditions dominated early trait variation at 4 years. Survival from Chikangawa provenance ranged from 21% (Dedza) to 54% (Chikangawa, Luwawa, Zomba, Thuchira); RCD from 1.6 cm (Thuchira) to 6.9 cm (Luwawa); and height from 1.2 m (Thuchira) to 3.1 m (Zomba). Zomba provenance excelled (66% survival overall; 89% at Luwawa; RCD 4.9 cm mean), Tanzania led height at productive sites, and Chikangawa underperformed consistently. Productive sites (> 50% survival) featured sandy loams, p > 10 mg kg −1 , CEC > 150 cmol_c kg −1 , and pH 4.2–4.9; failures showed P‐deficient sands (2.7–3.3 mg kg −1 ). Phosphorus and CEC strongly predicted growth; Zomba on P‐replete loams achieved > 65% survival. These findings demonstrate that early performance of Mulanje cedar is jointly governed by genetic origin and edaphic conditions, highlight Zomba provenance as a promising genetic resource for restoration and underline the need to integrate soil pH, phosphorus status and texture into provenance choice and site preparation to improve reforestation success. Integrating soil diagnostics will boost reforestation success, secure W. whytei recovery and guide endangered conifer conservation globally.

Ҳали таржима қилинмаган