Thuja green giant dropping branches

Question: Hello, We have a tall evergreen, I believe it is Thuja green giant. Recently I started seeing a lot of green branches on the ground. It appears the tree is dropping its branches from the top in an alarming rate. The tree trunk separates into 4, the falling branches are mostly from the inside. The pictures shows a few fallen branches, I have found dozens of them over the last week. It has been raining a lot in the last month, in case this have any relevance. Thank you for your help.

responder: An Ask Extension Expert Replied July 21, 2023, 8:29 AM EDT
response: Sorry to see this problem with your beautiful, mature trees. The photo of the dropped branches is not very clear but the point of breakage looks fresh rather than diseased, which suggests that you may have squirrels nibbling off branchlets for nesting material. It looks as though you may have utility wires close to the tops of your trees and as they have grown they may have become more accessible to squirrels traveling on the wires. There are other possible explanations for browning and dropped branches, but the branches would tend to be more brown and dried at the time of drop.  Fungal disease infections initiate in damp weather, particularly on trees that are stressed. Most of these are twig blight diseases that make tips of branchlets discolor and die. Look for tiny, black , pimple-like fungal fruiting structures on needles and branchlets, and cankers on branches in spring and summer to help identify the fungal disease present.  Several types of soft scale insects feed on arborvitae. Look for small, waxy white or glossy brown bumps on the needles. They cause stunting and discoloration.   Arborvitae can also "drown" from water soaked soil and inadequate drainage. Roots cannot grow well if they are constrained by dense soil which may also may create a "bathtub" around the root ball. In wet weather, water fills the tub and air spaces in the soil and does not drain, choking off oxygen and damaging the roots. Needles and entire branches die-back. Mulching too much can create a similar, overly wet, situation. You should have a certified arborist examine the trees to rule out incipient disease, check drainage and root conditions, look for squirrel nests and determine if trimming could reduce access.

responder: The Question Asker Replied July 21, 2023, 3:08 PM EDT
response: Thank you very much for your immediate and exhaustive response.It will help me not only with the current problem, but to take better care of the trees in the future. I have one follow up question- I am attaching a picture of the branches where they were cut. Does it look consistent with squirrels biting them? We have a lot of squirrels.Thank you very much again! Your help is much appreciated !On Fri, Jul 21, 2023 at 8:29 AM Ask Extension <<personal data hidden>> wrote:

responder: An Ask Extension Expert Replied July 21, 2023, 3:36 PM EDT
response: You are very welcome. I'm glad that we could help.  Yes, these angled, shredded cuts of healthy wood are made by animals. At that height and in our area squirrels are the most likely culprits and you may even be able to make out their little teeth grooves in the wood. I don't see any signs of disease in this photo that suggest a different issue. Be on the lookout! All the best, Leslie NYBG Plant Information Service

responder: The Question Asker Replied July 22, 2023, 11:35 AM EDT
response: Thank you very much Leslie!Your help is much appreciated ! DimitarOn Fri, Jul 21, 2023 at 3:36 PM Ask Extension <<personal data hidden>> wrote: