Halo-releasing
Research into ‘halo-releasing’ to prolong the life of veterans has been going on for the last 30 years. Haloing is based on the theory that as trees age, they become less tolerant of shade. When trees that began life in an open area become surrounded by younger trees, they suffer due to a lack of light. If the lower branches are shaded out by saplings, their lives can be shortened by 100 years.
How it's done
Area ranger, Chrissy and her team clear the encroaching trees that have grown up around the veterans in a 5m halo around the tree. Five years later, a further 5m band is cleared. ‘We do it gradually so as not to “shock” the tree,’ she says, ‘They’re very sensitive to changes in wind dynamics and humidity, so we have to be gentle or we could end up hastening their demise.’
‘Haloing is the exact opposite of automated commercial felling. You need to be careful not to clatter the veteran with the tree you’re removing,’ explains Chrissy. ‘We use hand chain saws and keep the heavy machinery as far away as possible to avoid ground compaction so that we don’t damage the roots or reduce the air pockets in the soil.’