Dead branches on your pine tree – why? Act now to save it

You’ll often see pine trees missing their lower branches, which have lost their needles and died, or been pruned off by the owner. Look at a tall Scots pine – some of this is normal. But when isn’t it normal? Fast action can be the only way to save your pine tree, and dying branches is an early sign.

Dead or dying branches on pine trees can occur following drought, lack of sunlight, winter injury or recent transplanting. Death of branches occurs when fungal cankers girdle individual branches, and is also seen in pine wilt disease and pine bark beetle infestation.

Pine trees that get plenty of sunlight and water should not routinely be losing lower branches unless your pine has grown very large and is shading them out with its own upper foliage.

There are so many species of pine (and so many diseases and pests) that it could make your head spin. I’ve pulled all the information together for you in an article that I hope will be much more straightforward so that you can work out what’s going on with your pine tree or trees!

If you think there could be an issue with your pine, reading this article will save you many headaches later on!

Dead pine branches due to drought

The first thing to consider is whether your pine’s getting enough water. This is going to be particularly relevant if you’re noticing dying branches after a prolonged hot or wet period.

When I say that pine trees really don’t like drought, I mean it. To take one example… in a Californian drought between 2012 and 2015, almost 90% of ponderosa pines in part of Sierra Nevada died!

It’s more likely that it’s drought-related if you have other pine trees nearby on your property that have the same issue.

Pine trees need to be watered weekly during dry periods to thrive. If you don’t, you can end up with excessive browning off and needle drop in some branches, followed by more of the tree. The tree tends to look brittle and sick.

Watering a pine means 30 minutes or so of soaking. Don’t just soak around the trunk – water the area under the canopy. You might need a sprinkler to do this, but a ‘soaker hose’ is a better idea, especially if you have a row of pines.

You can protect the roots from drying by applying around 4 inches of mulch around the base of the tree, in a circle of diameter around 5 feet. This helps rainwater (and the water you give it) to permeate into the ground, and stops the roots from drying out.

Almost every tree benefits from mulch!

And the simplest and best mulch in this case? Well, what do you find under a pine tree in a forest? Fallen pine needles! A pine tree will lose around one-quarter to one-third of its needles each year normally, between late summer and late autumn. Let them lie. Provided your tree doesn’t have an infection (see below), the needles provide an effective mulch and as they decompose they’ll return nutrients to the soil.

Otherwise, my favorite is to spread wood chippings, for a natural look.

Keep the mulch from touching the actual tree trunk, which likes to stay dry.

young dead brown pine tree
A young dead pine in late summer. Being young, it needed more frequent watering – and the lack of mulch has seen it outcompete for water by grass and weeds.

Dead pine branches and sunlight

Lack of sunlight causes the eventual demise of pine branches, starting at the bottom up.

The lowest branches get the least sun, so pine trees prioritize the tips of the higher-up branches when putting on new needle growth – as they catch the most sun that can be used for photosynthesis.

This is part of the natural growth pattern of pine in a forest, where minimal light penetrates to the lower parts. But it doesn’t always look good on your property, particularly as they go brown and bare first of all.

You may have planted your pine tree in a spot that’s too shady, so it’s sacrificing the bottom branches in favor of those that get more sunlight. This is a common issue when pines are planted too close together.

Thinning out your pines is a solution if you’ve planted too many, but if the pine’s in full shade because of, for example, your house, you may be better off planting another one in a sunnier spot.

If you’ve got dead, bare branches lower down, go ahead and prune ’em off – they’re no good to you or the tree.

The effects of recent pine planting

Have you planted your pine in the last 3 years? The more recently you planted it, the more relevant this section is.

‘Transplant shock’ occurs when a young pine is planted in the ground (often from a container) and its roots have to suddenly adapt to a new soil. Often I find homeowners plant pines in the middle of summer when it’s hot and the ground’s dry (late summer or autumn is the best time). This compounds the transplant shock effect.

Trees in shock can lost the majority of their needles and look like they’re at death’s door.

The solution is –

a. water it frequently – at least weekly, or twice weekly if the soil’s sandy

b. make sure you’ve got plenty of mulch around the tree (but as above, don’t pile it up against the trunk – leave a slight gap around it).

If you do these two things, most trees will make it. I wouldn’t worry much about applying fertilizer – let it adjust to its new environment.

Winter and spring branch death caused by ‘winter injury’.

Pine trees keep their needles on year-round, meaning right through the winter the tree has to endure the evaporation of moisture from them due to harsh winds – when deciduous trees have shed their leaves. So the roots need to keep on drawing water up in winter to replace what’s evaporating from the needles above ground. And is the ground’s frozen, they can’t get any!

Consider pine winter injury as the cause if:

  • if you’ve had a particularly cold or windy winter
  • if the dying branches are becoming evident in the spring
  • if the dead or dying branches are mostly on one side – this is usually the side that’s exposed to wind
  • If they might have got sprayed with salt – particularly pines along roadsides or driveways. Salt increases the risk of winter injury

I’ve written about how to protect pine trees from winter injury in this post.

Pine branch death due to girdling

Girdling means the branch’s flow of water and nutrients – through channels running just under the bark – has been blocked or interrupted, either by accident or disease. When this happens around the main trunk, the tree dies; when it happens around a branch, the branch dies.

If you’re only losing one or two branches, closely inspect the bark along the branch, especially near its base where it means a thicker branch or the trunk.

  • can you see where the has been snapped by wind, or has the bark been chewed at by an animal?
  • has a low branch (or even the trunk) been damaged by a lawnmower or trimmer?
  • can you see any cankers – sunken, wet-looking or oozing ‘wounds’ in the bark – a sign of disease.

If you’ve got tree damage from a lawnmower or trimmer, you can read more about tree damage and what to do in this post). Otherwise, if you think you have a canker, make sure you read on.

Identifying when you have a pine disease or pest

There are close to 150 species of pine and many different diseases, but there are a few particularly common ones that crop up time and time again that can cause pine branches to die back. Some of these affect other conifers as well as pines. Fortunately with a bit of guidance I can get you close to a diagnosis.

It’s important to find out if your pine tree’s diseased because no amount of watering, mulching or even fertilizing will rectify it and your tree may eventually die if you don’t stop it.

Cytospora canker disease

This fungal infection is prevalent worldwide (especially in the northern hemisphere) and, while it’s best known for attacking spruce trees, it readily attacks pines. It usually causes sporadic death of random limbs in pines, and needs to be identified as it can spread down the bark and eventually girdle and kill the tree – in the process it’ll weaken it and sap the tree’s growth and vigor.

Usually the needles on cytospora-infected branches will go brown or reddish brown between summer and autumn. In winter the needles start to drop off the branches, often leaving them bare.

Afflicted branches will display a canker – a seeping wound on the bark – often near where that limb meets a larger branch, or the trunk. Sometimes there’ll be crystallized white sap around the canker, where the abnormal sap has oozed out and hardened, or evidence of sap dripping downward from the canker. Normal pine sap is golden in color.

Cytospora infection is more likely to set in after times of wet, cool weather. Wet needles act as a breeding ground for the fungal spores.

Fungicides are not usually useful for cytospora canker. The disease can’t be cured; only controlled by removal of infected branches and by trying to prevent reinfection. If you think you have a branch that’s infected, it should be pruned off right away, but take care:

  • don’t cut through the canker – make sure you’re clearing it by a few inches of normal healthy branch as well.
  • clean your saw or pruners in between cuts with 70% alcohol (such as hand sanitizer) – lest you spread the infection from place to place
  • completely remove the branch, and if possible any fallen pieces, and if you can any fallen needles! These can act as inoculum – places from which cytospora spores can spread to the rest of the pine, or to other trees. The tree parts need to be burned or put in the trash – don’t mulch and spread them.

Pine trees that are weak – for example, growing in thin dry soil, or in a saturated patch – are more prone to getting cytospora infection.

White pine blister rust

If your pine tree needles are in clusters of 5 needles, you have a white pine. They’re all susceptible to blister rust – especially the western white and the beautiful eastern white, which is a personal favorite pine of mine.

The fungal disease has been known to affect any of the 5-needle pines (known as white pines) throughout the northern hemisphere. It causes death of individual branches one at a time, but can eventually lead to death of all the branches if the infection gets into the trunk.

White pine blister rust first appeared on the eastern side of the United States in 1898 and has continued to spread steadily since then. It has killed many pines and caused havoc with the pine timber industry in some areas.

This disease is a bit different in that it has another host – currant and gooseberry plants. If you have either nearby, check their leaves for brown spots. If you find some, you may need to get rid of them, as wind will spread spores to your white pine, infecting more needles (particularly when the needles are wet).

White pine blister rust also causes cankers in the branches or trunk, so get out there and inspect them for any abnormalities. They’ll usually be raised (as compared with the sunken cankers of cytospora) and may have unsightly blisters around the edges. You might even see a dead branch coming out of a canker on the main trunk. Again you can expect resin to be dripping from the cankers, or hardened and dried around them.

The needles of affected branches will turn orange, then red.

If you just have a couple of dying branches, you may be able to save the tree. As for cytospora canker disease, you’ll need to cut off any infected limbs plus a few inches of healthy branch on the other side of the canker, and clean your pruners thoroughly between cuts. Fortunately this fungus doesn’t survive on the ground so easily, so you don’t have to be as careful about getting any parts you sever off your property.

If you’ve already got cankers on the main trunk, you will have a hard time getting the tree to survive. It might be worth trying to carve out the canker (with a good margin) with a clean knife, if it’s a young tree.

Reduce the risk of white pine blister rust by not growing currants or gooseberries on the same property – so often, this is where the problem originates. It’s also good not to pack your pine trees together too closely – allow plenty of air flow so the needles can readily dry out.

Here’s a helpful video on white pine blister rust that’ll help you ID it.

Pine bark beetle

Consider pine bark beetle if numerous branches on the tree seem to be dying at once. The pine bark beetle has had a simple huge impact on the pine industry. It engraves tunnels under the tree’s bark, interrupting the flow of water and nutrients – it can often kill the pine, especially if it’s stressed from drought to start with.

Have a close look at your pine. Can you see:

  1. tiny burrow holes in the trunk’s bark
  2. sawdust material or lumps of resin on it (extruded from the burrows)
  3. needles turning red

If you peel off a tiny area of bark at the burrow sites, you might see mosaic-like burrow tracks made by the beetles, or find some grub-like larvae.

If you’re already seeing the above signs, it’s too late to start spraying the tree with insecticide. I would consider consulting a trained arborist at this point. These critters are tricky to deal with.

To prevent pine beetle infestation, keep pine trees well watered and avoid planting too many trees close together. Avoid leaving piles of chopped wood near your trees, as they can serve as a colony for them. See back at the start of this article for more information about watering pines.

I think this University of Wyoming Extension video is a good one if you’d like to know a little more.

Pine wilt disease

Consider pine wilt if multiple branches have died at once, but the needles have stayed on. This is an important disease to know about.

Pine wilt disease is an aggressive disease of pine caused by the nematode Bursaphelenus xylophilus, and it’s found throughout the whole of the northern hemisphere.

Laboratory assessment of samples is needed to confirm this infestation, but you’ll observe clusters of branches turning a lightish brown together, and within a couple of weeks the whole tree will look similar.

If you have a case of pine wilt, the tree is often dead within weeks. Unusually though, the needles don’t fall off the dead branches.

Pine wilt can be prevented by regular injections into the tree stump, but it’s too late to treat the tree once it’s infected. It’s important to contact an arborist if this happens, as you may need to have the tree professionally removed and disposed of – further infections will spell the end of the other pines on your property as well.

As always, if you’re really concerned about your pine, consult a trained arborist for professional input.

Dead branches on pine trees – a summary

  1. Make sure your pine’s roots aren’t drying out – give it some water
  2. If it has been planted recently, it may be transplant shock
  3. If it’s winter, or winter’s just passed – consider winter injury
  4. If in a shady spot, this could be the trouble
  5. Look for damaged bark along the dead limb. If it’s oozing or has dried resin around it, it may be a fungal canker
  6. Inspect the tree bark for oozing cankers and pine beetle burrow holes

I hope you found this article helpful!

When is it abnormal to have needles dropping from your pine tree? I’ve answered this for you in this article – check it out.

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