Pine trees

Question: Hello, I live in Arvada. About a year ago we planted 2 Austrian Pines and 2 Blue Spruce.  They are approx. 30-40 ft from a pond bank.  The pond was previously seeping but repaired prior to the plantings. (Additional top soil was brought in and the pond was dredged and lined with bentonite.) The pond is spring fed year round and fed by Farmers High Line Canal May-Oct. The pines are now showing signs of distress (needles are yellowing at tips). Our arborist who planted the pines believes the soil may be the problem. We have 10 pines further away from the pond that are doing fine.. Can you offer any advice.  I see you do soil samples but there are many choices and I wonder which if any you recommend? Thanks,  Liz

responder: Hania Oleszak  Replied April 18, 2023, 1:31 PM EDT
response: Hi Liz, Needle browning is often a sign of water stress or winter damage. Particularly because these trees are recent transplants, my inclination would be to think that they have either not been watered enough during their establishment. What has been the watering regimen for these trees?  Additionally, could you send me photos of the trunks (particularly so that I can see where the trunk meets the soil line)? Thanks! Hania

responder: The Question Asker Replied April 19, 2023, 11:08 AM EDT
response: Thanks for your reply Hania! I have attached 2 pics. The trees were planted by an arborist and were watered per his instructions.  The tree wells have remained intact.He thinks the issue may be r/t the pond because out of 10 trees planted, only the 3 closest to the pond (which had a history of seeping prior to repair) are showing stress.I can send soil tests but there are many to choose from on the CSU site.Do you see value in soil testing given that our pond is part of a larger network and also spring fed?  If so, what would be the priorities for testing?Thanks,LizSent from my iPad On Apr 18, 2023, at 11:31 AM, Ask Extension <<personal data hidden>> wrote:﻿

responder: Hania Oleszak  Replied April 19, 2023, 12:36 PM EDT
response: Hi Liz, At this point, I don't think it's likely that the pond is affecting the trees. For one, I don't think it's likely that the roots of the trees are accessing the pond, or anything that could be seeping out of the pond, yet, since they were just established last year. Secondly, I don't know what could be seeping out of the pond that would be cause for concern, particularly since it seems the canal is generally used for agricultural irrigation, so the quality of the water in your pond should be fairly good. It's hard to see from those last photos you sent, but it's possible that these trees were planted too deeply (normally you want to see the flare at the bottom of the trunk, rather than it looking like a telephone pole planted into the ground), which would contribute to stress for the trees. Conversely, if these three trees are planted out in the open more than the others, they may be more susceptible to winds, which can contribute to drought stress and winter damage (and therefore the browning of the needles). Winter damage is very common along spruce and pine trees here. Since the trees only have minor browning, you might consider waiting a bit and monitoring the trees. If the buds on the ends of the browning branches are still alive (which they probably are), new growth will candle out from the brown areas. At that point, the trees should continue to grow this season. It would be helpful to supplement the trees with water during prolonged dry periods in the fall/winter (particularly on days where it's above 40F) to help avoid winter damage. If you notice the trees are declining or not producing new growth, we can reassess the situation. Let me know if you have additional questions, Hania

responder: The Question Asker Replied May 23, 2023, 7:12 PM EDT
response: Hello,Thanks for your reply. I did end up bringing in a sample but don’t know how to interpret the results in terms of what it might mean to the Australian Pines and Blue Spruces that look stressed.  I wonder if you would have a look at it?Much appreciated,LizSent from my iPad On Apr 19, 2023, at 10:36 AM, Ask Extension <<personal data hidden>> wrote:﻿

responder: Hania Oleszak  Replied June 07, 2023, 12:02 PM EDT
response: Hi Liz, It looks like you have moderate levels of salts in your soils, which can potentially have adverse effects on some trees. Austrian pines and blue spruce generally are pretty tolerant to higher salt levels, so I don't know that the salt is causing the damage you've seen. Either way, to help flush that salt out, you'll want to irrigate the soil with good quality water so that you can leach some of the salts down the soil profile and out of the way. Other then that, the report indicated lower nitrogen levels, so you could consider fertilizing your trees. Here is a helpful resource that walks through how, when, and how much to fertilize: https://extension.umn.edu/trees-and-shrubs/fertilizing-evergreens#how-much-fertilizer-to-use-1340012. Hopefully this helps - let me know if you have any follow-up questions! Hania