No matter how drought tolerant your trees are, the recent changes in Australia's weather patterns may have taken their toll. Not only is Australia getting hotter, with 15 of the last 16 years producing 15 of the hottest years on record, but rainfall is decreasing too.
Unfortunately, even if the weather today is ideal for your trees, drought stress of two or three years ago may have finally caught up.
Trees Take Time to Show Stress
Australia is no stranger to drought. Trees in drought affected areas will suffer. However, external symptoms may not manifest for as many as 2-3 years after the drought event. The same applies to other types of trauma such as flooding or root damage due to nearby construction.
External Symptoms to Look out For
Though a single stress event won't necessarily kill your tree, it may take several years for your tree to recover. Provided its growing environment offers good soil drainage, ample nutrients and space for its roots, a stressed tree can recover.
However, you may see the external effects of the stressful event for the next several years. Signs of stress include fewer leaves, discoloured leaves, smaller leaves, early leaf drop, fungi on branches, and the death of twigs and branches. This can happen because the tree's food supply is depleted and in order to survive, it needs to sacrifice its leaves, twigs and even branches.
External symptoms can unfortunately signal that your tree is in a downward spiral from which it may not recover. However, just because your tree has no leaves at the moment in the height of summer, that doesn't mean that it is dead.
You will need to do the scratch test.
The Scratch Test Will Reveal if a Tree if Dead or Not
To determine if your tree is dead or alive, first test the twigs that you can reach. Reach up and bend them. A healthy twig should bend, and then split to reveal a stringy inner layer of green and white. A dead twig will simply snap easily. Perform this test on several small twigs throughout the tree's canopy. An abundance of dead twigs throughout your tree is not a good sign and could be an indication that the tree is dead.
To make sure, perform the scratch test. Go over to the trunk and using a small pocket knife or similar implement, scratch away a small piece of the bark. Underneath, it should be a healthy and vibrant green. Brown is an indication that that part of the tree is dead.
At this point, if you think your tree is dead, call an arborist to perform a more thorough assessment of the tree. They will be able to determine if there is any hope of saving the tree. If your tree has died, remove it as soon as possible. A dead tree can quickly become a hazard. Do not attempt to remove a large tree on your own; however, call an expert to remove it quickly and safely.