Tree Facts

/Tree Facts

Holes in Tree Trunks

Tree Facts|

Occasionally, holes develop in the trunk of a tree. Sometimes these are visible, but other times they are not easily detected. What causes this and will it kill the tree? The short answer is that a hollow tree may continue to thrive for many years, and the decay of the inside deadwood is a natural part of the life cycle of a tree. The centre of the tree trunk was once the sapling timber, and as the tree grows, stronger layers are built around this sapling wood, until the strength of the outer trunk is what supports the canopy. The trunk of a tree has two purposes – to support the canopy and to carry water and sap from the roots to the tallest parts of the tree. The wood in the middle of the trunk, previously the sapling, is no longer used for the transportation of food to the canopy, as each new layer of timber and bark take over that job. Bacteria invade the dry hardwood at the centre of the trunk, and as decay begins, insects and small animals make their way into the hollows created. Year by year the hollow parts extend within the trunk, and become visible from the outside. Larger animals may now make their home in these hollows. Unless the foliage of the canopy of the tree is showing signs of distress, there is no cause for alarm. Birds, possums, bats, maybe even tree kangaroos could make their home in your hollow tree. If the foliage on the canopy becomes sparse and discolours, then it would be time to confer with an experienced arborist regarding the future of the tree. If the tree trunk is unstable, not able [...]

Trees can get sunburned in cold weather

Tree Facts|

Did you know that plants and trees can get sunburned? Much like our sunburn, if a tree or plant gets too much strong sunlight it can develop lesions, or damaged spots which allows diseases to enter the plant’s system. This is called sun-scald. Sun-scald, unlike sunburn, does not occur in summer, near the beach. It occurs in cold climates, where there are extremes of temperature. Tree sun-scald often occurs in young trees, because the sapling has a softer exterior, more influenced by sharp changes in weather. Once a plant has been damaged by sun-scald, it cannot be repaired. Prevention is the only cure. Sun-scald is a winter time injury to tree trunks caused by unseasonally warm weather. The sun is low and warm, shining directly on the trunk of the tree. Deciduous trees will have lost their foliage and the trunk of the tree is more exposed to a low sun. The cells of the tree, previously closed due to the cold weather, open up as they would if Spring had arrived, only to be left vulnerable when the temperature drops quickly after the sun sets. The surface of the tree trunk is damaged, and quickly dies. If sufficient sun-scald has been experienced, the damage may cut off the water and sap supply to the foliage. This is very bad news for the affected tree. Remember when pruning larger trees and bushes, the additional sunlight to the tree trunk and plants below may cause damage. Rather than thinning the whole canopy, it would be preferable to raise the height of the canopy by lopping only the lower branches. This allows extra light generally, while still providing shade to the trunk and plants beneath. To prevent [...]

Widow maker gum trees, and why you should clear the deadwood

Tree Facts|

Australia is home to an enormous variety of Eucalyptus trees, which can grow to over 40 metres in height. Although they are naturally beautiful and house many species of Australian fauna, including koalas and possums, they can be a danger to humans in populated areas. Giant eucalypts have a habit of dropping heavy branches earning them the nickname of Widow Maker. These gum trees preserve their health during periods of drought or inadequate water supply by allowing some branches to dry out and break off – a sort of self pruning. As an increasing number of roads, buildings, concrete slabs and paths and other plants limit the availability and access to water for these tree giants, our suburban areas are particularly susceptible to the antics of the Widow Maker. The large trees are competing for water, as development channels rainwater into drains, instead of leaving it available to our native flora. Construction is limiting root growth and even damaging the existing root system, so that these trees are not able to absorb the amount of water required to maintain the health of the crown of the tree. Where there is not enough water, the tree will create blockages to certain branches in order to preserve the health of the rest of the tree. It’s a bit like losing weight for a human, and quite literally results in losing weight for the tree, because the branch eventually breaks off. Huge branches falling from 30 or 40 metres to the ground can do some real damage, and there have been recorded incidents of death to people due to this – hence the nickname. Damage to cars and buildings is common during storms or strong wind. Councils regularly [...]

Why do trees grow straight?

Tree Facts|

Have you ever wondered how plants and trees know which way is up? Even when they are growing on the side of a steep hill trees still manage to point themselves to the sky. All plants have a way to interpret gravity and use that sense to send their roots downward and their branches upward. In the top of new shoot, and in the bottom of a root, a cluster of cells are found that are continually dividing and therefore responsible for new growth. Inside these cells are miniature starch granules which are affected by gravity. These starch granules will always sit in the bottom of the cell, so the cell knows which way is down. Using auxin, a plant hormone, and a chain of signals, the dividing cells continually respond to this information from the starch granule and adjust their direction of growth to conform to their understanding of gravity. The root cells sending themselves in the direction of gravity and the shoot cells away from it. This phenomenon is known as gravitropism. This theory was tested in space by astronaut Andre Kuipers. He took seedlings out to space to see which direction they would grow. Without consistent gravity to guide them the little plants started shooting off in every direction. You might have noticed this happen with seedlings of your own. If you have ever had a pot tip over unnoticed, by the time you can adjust the plant, it may have already adjusted itself and started growing sideways and up towards the sky. So the lesson from all this is that plants are quite intelligent, and they will respond to instructions and guidance. Our experienced arborists are well familiar with the little [...]