Abstract ID: 3.8626 | Accepted as Poster | Talk | TBA | TBA

Widdringtonia whytei (Mulanje cedar), a critically endangered conifer endemic to Malawi, is threatened by over-exploitation and habitat loss, necessitating effective reforestation strategies. The success of these efforts relies on selecting provenances that are well-suited to specific environmental conditions. This study assessed the survival and growth performance of three W. whytei provenances (Chikangawa, Tanzania, and Zomba) in a four-year-old provenance trial across five sites in Malawi (Mt Mulanje, Zomba and Dedza and Luwawa, & Chikangawa highlands). It also analyzed the relationship between key soil factors and provenance performance. A randomized complete block design was used with five blocks per site, each containing three treatments of 49 trees planted at a spacing of 2.75m x 2.75m. Measurements were taken from a core area of 25 trees within each plot to minimize edge effects. Tree height (m) and root collar diameter (RCD, cm) were accurately measured, and survival rates were determined by counting surviving trees per plot. Soil samples were collected randomly from each 5×5 plot at all five provenance trial plots at a depth of 0.15 meters, with six samples collected from each subplot. Soil pH, electrical conductivity (EC), organic carbon content, total nitrogen, exchangeable bases, cation exchange capacity (CEC), total organic carbon (TOC) and phosphorus levels were analyzed using standard operating procedure for soil analysis. Analysis of Variance ANOVA using Minitab 16.1 was used to analyze height and RCD data, with means separated by Fischer’s least significant difference (LSD) at the 0.05 level. Survival data was analyzed using percentages. Zomba provenance demonstrated the highest mean survival (66.2%), with highest survival (88.8%) at Luwawa and RCD growth (7.68 cm). Chikangawa showed the least RCD growth (1.57 cm) lower mean survival of 31.2%. Available phosphorus (P) varied significantly; Dedza recorded a mean of 32.5 mg/kg, while levels at Thuchira and Zomba were critically low, averaging 3.0 mg/kg. Total nitrogen (N) varied between 0.11% at Luwawa and 0.63% at Thuchira, indicating site-specific differences in nutrient availability. Provenance and soil conditions significantly affect W. whytei survival and growth, with Zomba generally superior. Soil pH and phosphorus are crucial; matching provenance to site is vital.