Five permanent sample plots in Budongo, a semi-deciduous Ugandan forest, have provided stem measurements spanning six decades. These data provide a unique opportunity to investigate how the rainfall of the various measurement periods may influence apparent growth. Analysis detects significant seasonal effects but no longer term correlations with supra-annual (across years) variation in rainfall. The slowest growing trees show faster growth in wetter periods. However most stems show an apparent reduction in growth rates when measured over wetter seasonal periods. The observed variations correlate with differences in rainfall prior to stem measurement dates, and the patterns suggest rhythms that may reflect seasonal phenology in the predominantly deciduous forest. Short-term hydrostatic stem flexing rather than real growth is suggested as the predominant influence in the detected correlations. The magnitude of this effect may be about 0.1-1 % of diameter. This infuence may generate apparent volume discrepancies similar to a year's net growth (ca. 1-10m3ha-1), and thus presents a significant concern in interpreting growth data.
|Journal||Commonwealth Forestry Review|
|Publication status||Published - 1997|
- Hydrostatic pressure
- Permanent sample plot