- Older trees can be damaged through embers lodging on the bark or in the crotch of the tree
- Root systems sometimes survive even though the tops have been killed
- Root systems are damaged by burning organic matter or heat in the root zone.
- Fruit is scorched or baked
- Irrigation pipes were destroyed by the fire
- Defoliated trees can have limbs burnt after the fire
Although an orchard affected by fire and heat may look totally damaged, trees could recover productivity. It all depends on the degree of heat generated by the fire passing over the area where your fruit trees are, and the number of trees actually burnt out or damaged.
If trees have been killed outright, assessing the damage is straight forward. If trees are still alive (or appear to be alive), it may take several weeks before it is possible to assess the full impact on an individual block. The worst affected trees are most likely to be the border/edge trees closest to the fire front.
Just because a tree has been blackened and defoliated does not necessarily mean it is dead or going to die. It is important to take into account damage to the exterior of the tree (bark, limbs and roots) as well as the cambium layer (found just beneath the bark). The cambium is the layer of growing cells that produces the vascular system which conducts water and nutrient through the tree.
Cambium damage can be assessed by prising open the outer bark with a knife, axe or large screwdriver. If the tissue under the bark is moist and a creamy, white or a light tan colour the cambium is still alive, giving the tree a chance for recovery. Dead or damaged cambium will be dry and reddish/brown. Extensive damage to the cambium will kill the tree.
Heat and fire stressed trees may respond to the fire damage by re-shooting and perhaps even flowering. A decision can then be made as to how many trees have been killed outright and the viability can then be assessed. It is important to wait for regrowth to accurately assess tree viability. Trees that show signs of life may have been severely damaged on the side facing the fire and uneven regrowth may not provide a good opportunity to reform the tree in a balanced way.
Managing trees that show signs of life
If trees show signs of life (bark not shrivelling and new shoots starting to emerge), the irrigation system needs to be re-established so that trees can be irrigated and enable regrowth to mature. Trees may need to be protected from sunburn, particularly where defoliated. Trunks and large limbs can be painted with white wash or diluted water-based white paint to minimise sunburn problems.
Remaining fruit should be removed to prevent pest and disease build-up and unwanted stress on the trees.
Pruning should be delayed until regrowth has been established. Fertiliser should also be with held until there is sufficient growth to utilise it. It is essential not to force growth with extra fertiliser.
Long term viability of fire damaged trees
Experience from fire damage indicates that whilst trees may survive the fire damage they will take at least 2-3 seasons to return to cropping and may have seriously reduced potential. Trees may also continue to collapse from secondary problems after producing new shoots.
Decisions about long term viability and possible replacement should take into account the severity of the damage - tree age, variety, rootstock and planting densities. Younger trees, if not killed outright, may be easier to re-shape into productive trees and worth saving whereas older trees may not.
Note: Special thanks to all that has helped put this tip together.
Funds raised will assist our association to continue to provide support to individuals and families affected by fires. You can donate via Paypal or directly by transfering funds to our banking account. We request that you use the REFERENCE: FIRE SUPPORT for ease of administrative processing. Our support services, include assistance with items of first necessity, food and toiletries, general post fire safety advice, and access to legal advice and legal services practioners.
We are thankfull for whatever amount you donate, be it 25€, 50€, 100€, 250€, 500€ ... or any other amount that you feel is justified and you can afford to part with.
The simplest form is to make your donation online using your Paypal account, or your credit or debit card.
or click on the Paypal link below
SANTANDER TOTTA (LAGOS ALGARVE)
ASMAA Algarve Surf and Marine Activities Association
IBAN: PT50 0018 0008 02686698020 51