Trying to confirm if dying pine trees can be saved
I have 5 mature pine trees approx. 20 feet high in my back yard that have increasingly turned brown over the past 2 years and lost a lot of branches. I'd like to have an expert look at them to determine if they can be saved and if so, how. Please see the attached pics and notice after heavy winds, how the yard fills with branches. Thanks in advance for any assistance you can provide. Brent Betts
Howard County Maryland
These appear to be Japanese Cedar (Cryptomeria japonica); they are becoming more common in our area as a good substitute for Leyland Cypress and other large evergreens that aren't as well-suited to our growing conditions. The cause of their ailment is unclear, partly because symptoms can be similar among different infections, infestation, and environmental stressors.
One likely culprit - or perhaps the initial problem, at least - is the overly-wet weather we experienced in the past two springs. Many plants, especially those either not tolerant of wet soil or were planted in poorly-draining sites, suffered root suffocation from the waterlogged soils. Even though these appear to be on a bit of a slope, the soil underneath could still have drainage issues, especially from the initial compaction back when the homes were built. Because the weather during this wet spell was still cool and humid, plants were not yet water-stressed and symptoms above-ground would have been minimal. Even though they had fewer live roots, their water needs were low and the roots could keep up with demand. Then, as the hot, very dry weather hit in late summer/autumn, plants began to fail or show damage as tissues weren't getting enough water while the root system was recovering. Even irrigating plants at this time may have been futile, as too few roots remained to keep up with the water loss of the foliage. Evergreens are known for having delayed symptoms of root loss or water uptake issues - think of cut evergreens used as Christmas decorations...they are missing roots entirely and stay green for some time.
Unfortunately, this extensive damage is not something that can be treated with anything except time and normal plant maintenance. Keeping the remaining growth healthy and as stress-free as possible will allow them to regain what vigor they can. Do not fertilize, as this may exacerbate the situation and damage regrowing roots; it is also unlikely there is a nutrient deficiency in the soil. (Fertilization can trigger above-ground growth, which is not something a potentially root-imbalanced plant needs.)
Root rot, as the name implies, can include fungal infections in addition to simple insufficient oxygen levels, but the few fungicides labeled to treat this are used as preventatives, not curatives. Plus, multiple fungi can cause root rot, and not all are controlled by fungicides. This type of fungicide would also likely be a more expensive option than plant replacement, given the size of the plants (their root zone) needing treatment. It will not reverse damage - only help prevent its spread to still-healthy roots.
While it's possible the trees have contracted an insect infestation, the only one to cause branch death is a wood-boring beetle, which causes symtoms quite different from this. Scale insects can be a problem on occasion, but there is not visible evidence of there here, especially for such extensive browning. The fallen brown branches may be normal, in that Cryptomeria and many conifers typically shed their oldest, lower, interior branches with age, and these dead stems break off more easily with wind and weather. The fact that more may be falling than in prior years could either be simply a result of the plants' age or that their stresses are causing more rapid branch loss.
We realize that "wait and see" isn't an encouraging answer, but that is the best approach at this point. You can certainly remove all brown twigs and interior foliage - if ready to fall it will pull off fairly easily - to minimize the clean-up from each storm. While some degree of "bronzing" is normal in healthy Cryptomeria growth in winter, healthy growth should return to a vibrant green once temperatures moderate later in spring. Branches that don't and remain a yellow-brown or sickly yellow-green color are likely in the process of dying and won't be salvageable. In spring, you can then assess the health and appearance of the plants and determine if replacement makes sense or if they appear to be stabilizing.
Thanks very much Miri for the detailed response! I certainly don't mind waiting to see how things hopefully improve and the fact that you think there's a chance is cause to be optimistic. I've been in the house for 8 years and not sure when these were planted in the 12 years prior. There is another set of these trees on a crest of a small hill 3 houses away and they look really healthy.
Please see the attached pic of the backside of the trees where there is another type of tree growing along side of the pines just in case these two types shouldn't be close to each other.
The tree itself is o.k. though the area where it shades the evergreen may cause some needle thinning and drop. It is close, but doesn't necessarily need to be removed. When you may eventually need or want to make a screen planting, we'd suggest a diversity of plants as opposed to single species so that if a problem arises you don't lose the whole screen.