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Spring 2018 this arboretum contacted Torreya Guardians to inform us about morbity problems of their Florida Torreya specimens. Sarah Briggs sent us 8 photos, as below.
Editor's note: Torreya Guardians aggregates and posts photos on this website of Torreya specimens in a number of botanical gardens and arboretums. None of these institutions should be assumed as supportive of our goals to assist the "migration" of this endangered glacial relict poleward. Rather, such postings are intended to help all parties who aim to help this species thrive in the face of continued climate change.
April 2018 photos of morbiditySARAH BRIGGS (16 April 2019) wrote:
and subsequent correspondence to ascertain cause
We have some Torreya taxifolia on our property at The North Carolina Arboretum. I think perhaps you have been in contact with some of my coworkers in the past regarding them. I noticed a little yellowing last fall and it has gotten worse this spring. We have had record amounts of rain last year and this spring. The last few weeks have been much drier.
They have also started developing some little cones at this time. We thought maybe it was a fungal problem but not sure. I thought I would send you some pictures and see what your thoughts are.
Editor's note: The "little cones" mentioned are visible in the two photos left. They are typical male pollen cones.
• PAUL CAMIRE (1 May 2019):Hello Sarah - After taking a look at the pictures I have a couple questions Did you have any ice coating the plants during winter from freezing rain? Did you have any large trees nearby that were removed that were partially shading the Torreyas? Are Torreyas that get more shade than the trees in your photos mostly green/unaffected? Was there a drought in your area during summer of last year?SARAH BRIGGS (1 May 2019):
The reason I ask is from a few things I've seen and experienced. A person in New Hampshire has described similar damage to his foliage due to freezing rain. Snow doesn't cause this damage just ice for some reason. I've had some similar damage to some of my Torreyas [Michigan] that were in mostly shade and once they received more sun some of the needles burnt in a similar fashion over winter. It also appears that trees with a canopy over them do not appear to be affected by the cold and desiccating winter winds. If it ever stops raining here, I will try to send you a few pictures of winter/sun exposure damage of my trees.
Seeing the creek in the background, I don't think drought would be a problem for the trees. It could be excessive moisture, but I'm not leaning in that direction. The Torreyas at the Henry Foundation in Pennsylvania had two years of drought followed by a cold winter, and this resulted in the trees dropping their needles and giving up growth to their largest branches. They sent up tons of basal sprouts and new growth sprouted all along their trunks.
As long as the new growth from those extending buds stays vigorous and basal sprouts remain on the trees, then I think the Torreyas will survive whatever happened to them. I like to call Florida Torreya a true survivor! I also see that the male reproductive structures are present on a couple of your trees.
I am leaning towards ice/winter damage and that the trees will fully recover. I will check with a few other Torreya Guardians to get their thoughts. Two of them have possibly seen similar conditions as they are located in southeast TN and northwest GA. As soon as I get any further information I'll let you know....Thanks Paul. I will try to get down there and take some more pictures soon. It looked like the biggest Torreya only has green remaining on the tips at this point.PAUL CAMIRE (2 May 2019):
We have not lost any big trees at that site recently. We could never remember any occurrences of ice recently either.
All we have had are very wet conditions. I remember kind of noticing the change starting last fall. There is a smaller Torreya at a different site that looks a lot better. It is maybe showing some similar yellowing but in the very early stages. I will try to get a picture of it also.Hello Sarah. I heard back from a few people and my friend Jack in northern Georgia, not far from the North Carolina line, has had a similar experience. He has a tree in clay soil that has done the same thing as the trees in your pictures. He believes that the condition has to do with the soil moisture and the winter conditions. He said that after the tree had needle loss it made a recovery and the problem hasn't occurred again. The inner needles fell, but most of the branch tips retained their green coloring like yours.• PAUL CAMIRE:
I also received a couple pictures from the person in New Hampshire that had the ice damage, but it was obvious it wasn't the same problem since the ice discolored all the outer foliage and the inner leaves were untouched the opposite of what you are seeing.
Your answers to my other questions rules out my other thoughts. Winter burn would cause a bronzing of the leaves, but they would still hold green. When Torreyas are growing in shade and receive intense sun then their needles become bleached or mottled depending on if some dappled shade is still occurring.
So I believe your culprit to be the wet conditions, but the good news is that the trees should recover, but may be a bit unsightly until they drop those dead needles. The green branch tips and very vigorous top growth give me some reassurance that they will overcome this condition. I was looking at the growth on the trees and see that prior to this they had quite vigorous growth. We kind of judge the health and happiness of our Torreyas by how many buds are forming on the branch tips. If you see 3 to 5 buds extending then you know the tree is happy!
The hard thing with Torreya is that not very many people grow it and some of these conditions go unnoticed. One last thought: Is this area a lower spot/frost pocket? Perhaps a combination of the excess moisture and a frost pocket could cause this condition under certain conditions.
I appreciate your contacting me. If you ever have any questions I'd be glad to help. Please keep me informed on what the trees do and how they progress. There are definitely lessons to be learned and observations to be made.
Hopefully one of these years I will get a chance to visit your Arboretum. It looks like a very beautiful place.Connie - I was also contacted by Sarah Briggs and have responded to her after querying JACK JOHNSTON (GA), CLINT BANCROFT (TN), and DAEIN BALLARD (NH). I initially thought it was ice/winter damage, but after I talked to Jack he told me he had one tree in clay soil that did the same thing from possibly too moist of conditions. Jack's tree recovered and I think their trees will too.• CONNIE BARLOW (2 May 2019):
Given the previous dialogue, my sense of the situation is this:
(1) That male cones were formed this spring and now the leaves are browning on the same branch suggests to me that the problem was not a disease on that branch. Rather, something suddenly must have gone wrong below ground, as Paul Camire writes in his report.
(2) The clay layer hypothesis posted by Paul Camire above rings true for me. This is why it is always a good idea to look for a slope on any property where seeds or seedlings will be planted. A very steep slope is ideal for fending off deer herbivory and antler rubbing, but the distress caused by swamping suffocation of roots in flat zones with a clay layer is the main reason to always find a slope for planting Torreya. The ideal slope is probably southeast-facing; never southwest-facing except in northern states or very high elevations in the southern Appalachians.
See our Propagate webpage for a compendium of ideas, observations, and suggestions that volunteer planters have contributed over the years.
(3) Finally, this helps me understand what I saw at Cox Arboretum (northwest Georgia) during my visit there 14 March 2019. I haven't edited the videos I took there yet, but I recall an otherwise healthy looking Florida torreya that had several lower branches with healthy green tips but missing its prior year leaves inward on those branches. My sense is that prior year leaves normally stay healthy and photosynthesize for no less than 5 years. So when I do watch and edit the videos I will look for that. Strangely, though, the much older Torreya nucifera right next to it was thickly branched and seemingly had lost none of its usual prior year leaves. However, the Fusarium that causes stem cankers in Florida may also show the same early symptoms. Go to this webpage section on the canker disease and scroll down to see the disease photos I took in Torreya State Park, FL, January 2004.
CONCLUSION: I guess I'll have to create yet another new webpage on the Torreya Guardians site. This one will aggregate all the DISEASE PHOTOS (and corresponding interpretations), with links to key sources. More work to do!
SARAH BRIGGS (3 May 2019) contributed 5 additional photos, with this message:
"I think our Torreya is having a new flush of growth on the branch tips. The largest one was hit the hardest and only has a flush of growth at the very top of the tree."
List of all EX SITU PLANTINGS (since 1850), 24 pages in PDF, by Paul Camire, 2018.
Types of plantings/sites documented, 25 pages in PDF:
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