Summary
Despite the cold weather during the last week, with snow on high lying ground and a few flakes on the Witwatersrand campus, where the Johannesburg spore trap is sited, tree counts rose steadily and significant counts were detected in Johannesburg and Bloemfontein, while at other sites, the variety of tree pollen increased.
Cape Town
Tree pollen dropped below the significant levels due to low temperatures with snow on Western Cape mountains, some rain and gusting wind. Trees were sumac (Anacardiaceae), cypress (Cupressaceae), waxberry (Morella), mulberry (Moraceae), gum (Myrtaceae), pine (Pinaceae) and yellowwood (Podocarpaceae). Weeds were the daisy family (Asteraceae), sedges (Cyperaceae), erica (Ericaceae), spurges (Euphorbiaceae), mint (Lamiaceae) and bulrush (Typhaceae) and grasses were low, as were moulds.
Johannesburg
Significant tree pollen was seen at this site, dominated by plane (Platanaceae). Other trees included hackberry (Celtis), cypress (Cupressaceae), yellowwood (Podocarpaceae) and oak (Quercus). No weed pollen was detected and grasses were low, as were moulds.
Pretoria
At this site, trees would be low but varied and might include cypress (Cupressaceae), pine (Pinaceae), false olive (Buddleia), karee (Searsia), mulberry (Moraceae), poplar (Populaceae), pine (Pinaceae), birch (Betula), gum (Myrtaceae), plane (Platanaceae), oak (Quercus), willow (Salicaceae) and elm (Ulmaceae). Weeds might be the daisy family (Asteraceae), goosefoot (Chenopodiaceae), sedges (Cyperaceae), erica (Ericaceae), spurges (Euphorbiaceae) and iris (Iridaceae). Moulds would be low. 6-year means were used, but we are pleased to report that the spore trap for this site is now repaired and en route back to Pretoria.
Bloemfontein
Tree counts soared to high levels at this site and included birch (Betula), false olive (Buddleia), cypress (Cupressaceae), hackberry (Celtis), pine (Pinaceae), the dominant tree plane (Platanaceae), poplar (Populaceae), yellowwood (Podocarpaceae), karee (Searsia) and elm (Ulmaceae). Weeds were low and included sedges (Cyperaceae) and caltrops (Zygophyllaceae) and grasses and moulds were very low.
Kimberley
Trees at this site would be low and might include cypress (Cupressaceae), karee (Searsia), poplar (Populaceae), false olive (Buddleia), ash (Fraxinus), birch (Betula) and olive (Oleaceae0. Weeds could be the daisy family (Asteraceae), slangbos (Stoebe-type), sorrel (Rumex), erica (Ericaceae), figworts (Scrophulariaceae) and knotweed (Persicaria). Moulds would be low and ferns (Polypodiaceae), might be seen. 6-year means were used due to courier failure.
Durban
Trees would be low but varied and might include acacia (Acacia-type), cypress (Cupressaceae), mulberry (Moraceae), pine (Pinaceae), birch (Betula), sumac (Anacardiaceae), cedar (Cedrus), hackberry (Celtis), sweetgum (Liquidamber), pine (Pinaceae), yellowwood (Podocarpaceae) and beech (Fagus). Weeds would be spurges (Euphorbiaceae), nettles (Urticaceae), sedges (Cyperaceae), the carnation family (Caryophyllaceae), plantain (Plantaginaceae) and knotweed (Persicaria). Moulds would be low. 6-year means were used due to courier failure.
Gqeberha
Pollen and mould concentrations were low at this sampling site. Trees included Australian pine (Casuarina), waxberry (Morella), cedar (Cedrus) and pine (Pinaceae). Weeds were ice-plants (Aizoaceae) pigweeds (Amaranthaceae), sedges (Cyperaceae) and erica (Ericaceae).
George
At this time of the year all pollen concentrations would be low. Trees might include sumac (Anacardiaceae), ash (Fraxinus), poplar (Populaceae) and acacia (Acacia-type) and weeds might be the daisy family (Asteraceae) and knotweed (Persicaria). Moulds would be low. 2-year means were used. Progress is being made to relocate the sampling site.
Reference Range
Grass: Low: 0-5 Moderate: 6-20 High: 21-200
Trees: Low: 0-15 Moderate: 16-90 High: 91-1500
Weeds: Low: 0-10 Moderate: 10-50 High: 51-500
Moulds: Low: 0-900 Moderate: 900-2500 High 2500-25000
Unit: per cubic metre