Although Christmas is a symbolic time for birth, I can not but help thinking of resurrection when I see Dokmai Garden‘s ‘Star of Bethlehem’ (Vitex canescens, Lamiaceae) come back from certain death. Blogging about this during Easter would not be suitable, since many native deciduous trees are dormant at that time and not so photogenic.
The formerly tall Star of Bethlehem tree apparently drowned during the torrential rains of 2011; green leaves falling and branches drying. In early April 2012 I and French landscaping student Bruno Pecontal decided to cut it down. A shoot emerged from the stump not long ago, and then a huge fruitbody of a polypore.
This fungus may not necessarily be pathogenic and is hopefully just cleaning up the dead wood, but I keep observing the development of my dear patient.
At Dokmai Garden there are more examples of resurrection:
My latest student Mia, 8 months, points out the exact position of a scar from a surgical cut I made a few years ago due to death of the top shoot, caused by an attack by a borer. In this case, determining which borer is hard (not the same tree as in the previous blog). The tree is a pink shower (Cassia bakeriana, Fabaceae).
The new side shoot gradually overgrew the exposed stump and completely sealed it as if it never existed. The lower part below the diagonal cut with more lichens is the old stem. Of course such a stem is probably more vulnerable to storms, but the alternative, becoming termite food, more gloomy.
A Javanese cedar (Bischofia javanica, Euphorbiaceae) was also attacked by borers making its stem weak, and it fell before my eyes during a slight wind. I cut it down. New shoots emerged from the stump, but they were mysteriously killed by the gardeners who apparently thought I wanted to kill the tree. After explaining the circumstances leading to its original felling, the second wave of shoots now successfully aim for the sun.
Dokmai Garden’s tallest propeller tree (Dipterocarpus tuberculatus, Dipterocarpaceae) snapped before my eyes during a very heavy rainstorm earlier this year. I left the tall stump due to biodiversity reasons, i.e. promoting mushrooms, staghorn beetles, woodpeckers and raptors. To my joy this scarred hero was not down yet. We shall see if it will recover, or if this is the last futile effort to cling to life. It still wears soot on the bark from the last fire in 2005.
What can a regular monsoon gardener learn from these observations? Firstly, do not assume a dear tree is dead for ever, in spite of pathetic remains. Give it a chance, at least a few months of rainy season. Secondly, if you wish to move a smaller tree or shrub, cut it down and move the root ball. Surprisingly often the root ball recovers, while an effort to move an entire sapling with loads of branches and green leaves, may lead to desiccation and death. Thirdly, if you do want to kill a tree, do not assume that cutting it down is sufficient. Keep monitoring and keep pruning away brave attempts of recovery until the nutrients are depleted.
With the examples above in mind, why would a monsoon gardener care about proper pruning or stay away from hammering nails into trees? It is all about statistics. The chances for survival and prosperous growth increase with minimized damage to the tree, although some individuals may recover surprisingly well from extensive trauma. With bad luck, all it takes to kill a tree is a tiny wound in the bark, allowing a truly pathogenic fungus a stronghold.
Text & Photo: Eric Danell
(Precipitation report: following the driest rainy season ever recorded at Dokmai Garden, with jacaranda blooming and teaks shedding leaves prematurely, this November was the rainiest ever recorded; 34 mm at five occasions: November 7th: 16 mm, November 12th: 2 mm, November 13th: 6mm, November 25th: 8 mm, November 27th: 2mm. The computer models at the Climate Prediction Centre have downgraded their warnings about an upcoming El Nino, predicting a neutral or weak El Nino. That is very good news for the Chiang Mai gardeners who need to recover from the wet 2011 and the dry rainy season of 2012. On December 2nd we received 3 mm of rain).