Page 25 - Landscape-Issue123

The coppice growth of this Combretum erythrophyllum was never pruned, resulting in its shrub-like
appearance

Searsia pendulina with unmaintained coppice growth
negatively impacting the tree shape

Example of a ‘missing tree’. There is proof that a tree
was once planted in this location but that it no longer
exists

Research team taking plant measurements Examples of bark harvesting were identified mostly Cable ties and other materials left on the stems of
as data for the study on Combretum trees trees

known in urban forestry as it contributes (33%), were dead (11%) but still remained vandalism, soil compaction and improper
greatly to the reduction of catastrophic in the planting location or were seriously planting techniques could have contributed.
losses resulting from insects or diseases. damaged (8%). It is therefore estimated that The obvious lack of proper tree maintenance
Four species (Celtis africana (30%), only approximately 75 866 of the trees had identified during the study could also have
Combretum erythrophyllum (30%), Searsia survived by 2018, resulting in a 37% survival presented challenges for the successful
lancea (16%) and Olea europaea subsp. rate. The high mortality rate of these trees survival of the newly planted trees.
africana (14%) made up the bulk of the is inconsistent with published international
planting. results in northern hemisphere countries. The study estimated that more than
However, if the trees that were given to the half of the trees required some form of
The field survey revealed that only 43% of residents and businesses to plant were still maintenance. Approximately a quarter of
the trees on the register could be located alive, the survival rate of the project would the trees required the removal of coppice
in 2017, estimating that only 89 644 of the improve to approximately 60%. growth to create a single stemmed tree
206 276 planted were seen to be existing. and just less than a third required structural
Unfortunately, 15% of these trees were This study could not determine the pruning to improve the shape of the tree. A
also “missing,” meaning that they either definitive reasons for the low survival rate, number of trees needed dead branches to be
consisted mainly of coppice growth (48%), and it is estimated that a combination of removed, removal of constricting elements
were absent from their planting location factors such as water and nutrient stress, (wires and cable ties) found around tree

Landscape SA • Issue 123 2023 23