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Pine trees are evergreens that can grow for centuries. When you see anything close to resembling a pine tree dying from the bottom up, take action.
A wait and see approach is ill-advised. The faster a problem is addressed, the better chance there is of the pine tree surviving.
This is particularly true for species that only have two to three needles per bundle. The fewer needles per bundle, the more susceptible the tree is to disease. More so on younger pine trees.
The majority of pine trees are only considered mature once they’ve been growing for up to 30 years. Until they reach that stage, treat them with care and keep an eye out for growing problems.
One of the more sinister problems is the signs of a pine tree dying from the bottom up.
Important: It Might Just Be Drying!
Before panicking and reaching for the pruners to get cutting away at the ill looking brown branches, take a second to check the soil.
Pine trees are not drought tolerant and they need full sun. That means that they are in constant need of well-irrigated soil.
They do not long for much, but without full sun and enough water and the right soil types for nutrients, they won’t have enough energy to fend off pests of diseases. Plant them in the right locations and they defend themselves in nature with very little help.
If the soil dries out, the pine needles will dry out too. It starts from the bottom and works upwards.
Why it happens is another story more suited to a science journal, but the basics are, when the soil dries out, the tree sends moisture up to the higher branches leaving the lower branches to dry out first.
Quite the smart tree because once the soil is irrigated, the bottom branches will get the moisture much faster than the top branches.
Add some water, wait a bit, and see if the tree perks back up.
How Much water Does a Pine Tree Need?
As a guideline, a pine tree should be getting about an inch of water every week. In the better weather when there is not much rainfall, gardeners need to step in and irrigate the soil to stop the pines from drying out.
Use Mulch to Stop Pine Trees from Drying Out
A 6-inch layer of mulch locks moisture in the soil. Without mulching around the base of your pine tree, it is likely to dry out faster.
Suitable materials to use as mulching for pine trees include a mix of a redwood, pine, or oak. You can buy wood chip mulch from most gardening centers, or online.
Better is to source it locally. Most areas have arborists (local tree surgeons) and some of those will have wood chippers to get rid of either fallen trees, or trees that have collapsed and they’ve been called to clear it.
Healthy trees get put through a wood chipper, then you have the natural byproduct of real wood to use for mulch. It’s a far better choice of mulch than nutrient lacking straw. Besides, a wood mulch breaks down slower so it will last for longer.
Beyond that, it is what pine trees would have if they were to be grown in the forest. Forest floors are nutrient rich because it is only what falls from other trees. Wood chips are part of the tree ecosystem. Use it to your advantage.
Once you have mulch down and are confident that there’s plenty of moisture in the soil, run through the checklist below to find out what may be behind pine trees dying from the bottom up.
Pine Beetles and Bark Borers
The seeds that drop from pine needles are nutritious food for the local wildlife. The bark of the tree is a habitat for pests that can destroy pine trees from the inside out.
The pine beetle is one of the most destructive. Under 1cm in length, they are difficult to spot. The damage is not.
These beetles bore into the bark of the tree. Like when you drill into any wood, dust sprays outwards. Holes with sawdust surrounding them is indicative of a bark boring beetle presence. Rarely are they alone.
When these are present in high numbers, the damage becomes noticeable. The foliage changes color from its usual green to a duller shade, to yellow, then begins browning. It looks like its dying.
If you suspect there is a pine beetle presence, consult with your local arborist because healthy pine trees defend themselves. A borer presence is a symptomatic problem of inadequate growing conditions.
The most common reason for borer infestation is a lack of sun or water.
When the tree has low energy, it cannot produce the poisons nor the sap it needs to fight an insect attack, or the diseases they spread.
Eradicating a Pine Beetle Infestation Is Not Easy
In instances when there is more than one pine tree, expect to lose it. Crowded pine trees too close together are often a cause of weakened trees being attacked.
They lack the sunlight and water resources for the high energy they need to survive.
In unsuitable growing conditions, it leads to the infested tree needing to be removed to prevent the beetles from spreading.
Diseases That Can Kill Pine Trees from the Bottom Up
Diplodia Shoot Blight
This is a shoot tip disease caused by the Diplodia spp. Fungi. It can be present on trees for years without causing any deterioration.
The damage happens when the tree is weakened. That could happen if perhaps other plants or trees were planted too near to the pine, or improper pruning.
The damage this causes is browning on the lower part of the tree, similar to a shade of brown like straw. The dead branches and needles will have a sticky resin coating them.
Sometimes it shows as white, other times it is translucent, so you wouldn’t know until you picked up dead twigs without gardening gloves on. The bottom of the pine tree is the first to be affected with Diplodia shoot blight.
Some pine trees are highly resistant to this. Others are more susceptible.
The ones at highest risk are the pine trees with the lowest needles per bundle.
The maximum number of needles per bundle is 5. The majority are either two or three.
The species of pine trees most susceptible are the Austrian pine, Ponderosa, Scot’s pine, Red pine and the Jack pine tree. Species of 5-needle pine trees have a high resistance to Diplodia.
While this can lay dormant on trees for years, it is when the tree is weakened that the fungi strikes. Healthy pine trees have a strong defensive system so if this does strike, there will have been a trigger.
Since this starts on the lower part of the tree, the only way to stop it from spreading is to remove the diseased branches. Pruning should be done in dry conditions, and younger shoots can be treated with a preventative fungicide labelled for use on pine trees.
Home gardeners can apply the fungicide to young pine trees following the directions on the product label. For mature pine trees, an arborist should be consulted who has the experience and the tools to deal with tree diseases.
Red Band Needle Blight
Red band needle blight is caused by Dothistroma. It is a fungal disease that can be fatal. Particularly susceptible to this is the Corsican pine tree (black) species.
The symptoms start on the lower part of the tree showing needle tips turning brown. As the fungus spreads, the tips of needles turn red to brown, but the base of the needles remain green.
The blight appearance shows most in the fall when the tips look like they are water soaked, turned brown, then slightly yellowing below the tip before a red band appears further down. Beneath the red band, the rest of the needle is its usual green.
Treatment for Dothistroma disease can be done using either copper-based fungicide or a product containing mancozeb applied in the summer.
Annosus Root Rot (Butt Rot)
This is another fungal disease that can be fatal to pine trees. The Heterobasidion annosum fungus attacks the roots of the tree. But, unlike the majority of plants affected by root rot, it is not caused by overwatering.
The cause is most often the fungus entering the plant through an open wound. That could be from a pruning wound or accidentally bumping the tree with a string trimmer.
The two species of pine trees most susceptible are the Loblolly and the Slash pine.
Once the fungus is present, it spreads through the heartwood down to the roots where it forms what is called a conk. These are brown on top, and under them are small white pores.
As this disease starts in the heartwood and spreads downwards to the roots, the bulk of the pine tree will either be dead or dying. As the tree is weakened it will be more susceptible to toppling.
If it’s near any structures or could pose a risk to people if it were to fall, an arborist should be consulted to remove it. This is the same for any tall tree be it a fir, conifer or even an ornamental.
If it poses a hazard, have it removed.
The best way to care for pine trees is to only prune when absolutely necessary.
So long as the bulk of the tree gets full sun, has plenty of space for air circulation, and gets an inch of water a week, the tree will have enough energy for photosynthesis, and that’s what gives it the strength to fight diseases and the pests that carry them.