Veldbrandnavorsing in die Struikmopanieveld van die Nasionale Krugerwildtuin

Abstract

Die geskiedenis van veldbrand en die ontwikkeling van die huidige brandbeleid in die Nasionale Krugerwildtuin, Republiek van Suid-Afrika, word bespreek. Aandag word gegee aan die ligging en uitleg van die brandproefherhalings in die struikmopanieveld. Die metode van opname van die houtagtige komponente en die veldlaag word bespreek, sowel as die kriteria wat gebruik is in die vergelyking tussen brandbehandelings. 'n Fitososiologiese tabel van die verskillende persele is opgestel met spesifieke verwysing na die verskille in grondsoorte en hoe dit die floristiese samestelling bei'nvloed. Uit die resultate wat verkry is, is dit duidelik dat meer frekwente brande 'n nadelige invloed op die veldlaag het. Dit hang egter grootliks at van die seisoen van diejaar waarin gebrand word, sowel as die reenval en gepaardgaande opbou van brandbare materiaal. Brande in Augustus, Oktober en Desember is strawwer en rig meer skade in die veldlaag aan. In 'n nat siklus word die houtagtige komponent beter beheer deur 'n meer frekwente brand, maar as dit in 'n droe siklus toegepas word, kan dit lei tot bosindringing. 'n Oorwegende gevolgtrekking van hierdie studie is dat 'n brand* beleid wat nie daarop ingestel is om die natuurlike regime sover moontlik te simuleer nie, tot veldagteruitgang kan lei.


Veld fire research on the mopani shrubveld of the Kruger National Park. The history of veld burning and the development of the current burning policy in the Kruger National Park, Republic of South Africa, are discussed. Attention is given to the siting and lay-out of replications of the experimental burning plots in the northern mopani shrubveld. The method used for syurveying the woody and herbaceous components and the criteria used for comparing different burning treatment are explained. A phytosociological table of different plots is presented with special reference to differences in soil types and its influence on floristic composition. The results obtained show that more frequent burns have a detrimental effect on the herba-ceous vegetation. This is primarily dependent on the amount of accumulated fuel which in turn is influenced by the season and amount of rainfall. The August, October and December burns are more severe and cause more damage to the herbaceous field layer. In a wet cycle better control of the woody components is obtained with more frequent burns, but when applied during a dry cycle it may lead to bush encroachment. A major conclusion is that a burning policy which is not aimed at simulating the natural regime as far as possible, may cause deterioration of veld conditions.