Tree expert gives a talk at NCKU
Tainan, Taiwan, May 18, 2015
The National Cheng Kung University (NCKU) campus is full of greenery, and every tree is a valuable asset to the institute’s wildlife. In order to provide optimal care, Professor Dong-Chi Liu from the National Chung Hsing University was invited to give a talk on tree planting at NCKU Y. S. Sun Green Building Research Center on May 14.
Professor Liu gave a thorough introduction on tree anatomy, the correct method of pruning trees, and how to treat diseased trees.
Through outdoor demonstrations, he emphasized the environmental impacts of trees. Using a penetrometer (soil hardness tester) as an example, he described how overly hard soil could be detrimental for tree root development, and also modelled the standard method of “loosening” soil and revitalizing soil layers.
According to Liu, in order to grow taller, trees will exhibit apical dominance, where the growth of lateral buds are inhibited, in order to better stimulate the growth of apical (tip) buds and the central trunk. However, when the apical bud is damaged, the growth of lateral buds are stimulated, and “unstructured branches” are formed, which have a more fragile mechanical structure. As such, “decapitation-styled” trimming is an incorrect method of pruning, and could lead to higher risk of tree branches snapping due to strong winds.
Trees need to be trimmed according to their structure, Liu also points out. When topping (removing the crown of the tree), one needs to find a lateral branch that is capable of substituting the trunk, and also take care to cut diagonally, in order to prevent the growth of mechanically weak side branches. If lopping (removal of side branches), then one must not cut too deep, as this could lead to unfavorable wound healing, and decay fungi may invade the opening; leaving too much is also not recommended, as it could impede tissue covering of the wound.
Trees are also susceptible to illness, and common treatments include surgery and injections. However, says Liu, some cases of inefficient tree growth actually has no relation to illness, and stems from a lack of sensitivity during the planting process. For example, some people neglect to remove the plastic covering of the plant when transplanting into the earth; sealed by the plastic bag, the plant is unable to stretch or absorb the surrounding nutrients, and has no hope of growing well.
The habitat environment is essential for tree growth, and poor drainage faced by pavement and flower bed constructions and hard soil can all lead to insufficient soil oxygen supply, leading to root respiration decline, thus causing root decay and decrease in mechanical strength. As such, the tree is more prone to falling when faced with strong winds.
The NCKU tree maintenance workers in attendance responded that the talk was very informative. When taking care of the campus vegetation, though they are careful to maintain the aesthetics of the plants and to avoid decapitation-styled pruning, they did not know that there were so many underlying sciences that affect the mechanical structure, and promise to be even more vigilant when pruning trees in the future.
Enditem/wan-ling yi
The National Cheng Kung University (NCKU) campus is full of greenery, and every tree is a valuable asset to the institute’s wildlife. In order to provide optimal care, Professor Dong-Chi Liu from the National Chung Hsing University was invited to give a talk on tree planting at NCKU Y. S. Sun Green Building Research Center on May 14.
Professor Liu gave a thorough introduction on tree anatomy, the correct method of pruning trees, and how to treat diseased trees.
Through outdoor demonstrations, he emphasized the environmental impacts of trees. Using a penetrometer (soil hardness tester) as an example, he described how overly hard soil could be detrimental for tree root development, and also modelled the standard method of “loosening” soil and revitalizing soil layers.
According to Liu, in order to grow taller, trees will exhibit apical dominance, where the growth of lateral buds are inhibited, in order to better stimulate the growth of apical (tip) buds and the central trunk. However, when the apical bud is damaged, the growth of lateral buds are stimulated, and “unstructured branches” are formed, which have a more fragile mechanical structure. As such, “decapitation-styled” trimming is an incorrect method of pruning, and could lead to higher risk of tree branches snapping due to strong winds.
Trees need to be trimmed according to their structure, Liu also points out. When topping (removing the crown of the tree), one needs to find a lateral branch that is capable of substituting the trunk, and also take care to cut diagonally, in order to prevent the growth of mechanically weak side branches. If lopping (removal of side branches), then one must not cut too deep, as this could lead to unfavorable wound healing, and decay fungi may invade the opening; leaving too much is also not recommended, as it could impede tissue covering of the wound.
Trees are also susceptible to illness, and common treatments include surgery and injections. However, says Liu, some cases of inefficient tree growth actually has no relation to illness, and stems from a lack of sensitivity during the planting process. For example, some people neglect to remove the plastic covering of the plant when transplanting into the earth; sealed by the plastic bag, the plant is unable to stretch or absorb the surrounding nutrients, and has no hope of growing well.
The habitat environment is essential for tree growth, and poor drainage faced by pavement and flower bed constructions and hard soil can all lead to insufficient soil oxygen supply, leading to root respiration decline, thus causing root decay and decrease in mechanical strength. As such, the tree is more prone to falling when faced with strong winds.
The NCKU tree maintenance workers in attendance responded that the talk was very informative. When taking care of the campus vegetation, though they are careful to maintain the aesthetics of the plants and to avoid decapitation-styled pruning, they did not know that there were so many underlying sciences that affect the mechanical structure, and promise to be even more vigilant when pruning trees in the future.
Enditem/wan-ling yi
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