Mzabalazo Ngwenya, a Biometrician at the Agricultural Research Council, will present the Department of Statistical Science seminar with a talk entitled, ".Some Problems in Forestry and Ecology Related to Stand Management"

Mzabalazo obtained a Masters in Mathematical Statistics from the University of Cape Town in 2010.

We look at two forestry related problems on two spatial scales. The first problem which is on a regional scale encompasses the problem of managing, with the intention of eradication, of stands over run by an invasive tree species, Acacia, better known as wattle. This species threatens the local flora and fauna where it establishes so its control is very important so that biodiversity is preserved. Here the aim is to characterise the Acacia seed-bank size and its relationship with stand characteristics, in particular average stem diameter, to inform management strategies.  This problem is solved by generic application of generalized linear mixed models to identify the keys drivers of seed bank size as well as non-linear quantile regression to better understand these relationships.  The second problem is focused on Guava wilts disease spread in orchards which generally just cover a few hectares. The aim here is to characterise the disease propagation dynamics in order to formulate strategies to control the spread of the disease and minimize tree loss within orchards. For this problem spatio-temporal models are developed and applied in order to model the disease spread.