Pinyon tree is growing on the tips but has lost all inner needles - is this normal?

Question: Hi there, we planted a mature pinyon tree in our yard about 2 years ago. This year, it appears to have a lot of new growth on the tips of its branches. However, if you poke your head inside of the tree, there are no needles - just sticks. Is it normal for a pinyon to only have green needles on its exterior and nothing but sticks on the inside? Would it help the tree at all to prune some of the twigs that don't carry any needles? Thanks!

responder: Jeff C, Master Gardener Volunteer Replied August 14, 2024, 2:49 PM EDT
response: Hello there and thank you for using Ask Extension.   I am not seeing any signs or symptoms of pests on your tree.  This is a good news.  Is there any sap coming out of the trunk or branches that I am not seeing?  However, based upon your photos, the canopy does look a little sparse. This is probably due to water, either too much or too little. Pinons only need 9 to 14 inches of water per year, once they are established.  However, your young tree is not established yet. How much are you watering your tree?    Here's a nice plant talk on pinon pines that describes their requirements.   https://planttalk.colostate.edu/topics/trees-shrubs-vines/1748-pinon/  To directly address your question, you may need to adjust your watering.  Your newly planted tree is still in the "root establishment" phase.  Generally speaking, this phase lasts as many years as the diameter of the tree trunk when planted. Looking at your tree, it appears that the diameter of your tree is about 3 - 4 inches.  That means it will take 3 -4 years for the tree's roots to become established.    During this establishment phase, your tree has different watering requirements.  In the case of a 2-4 inch caliper tree, that means it needs to be watered every week during the growing season.  The mantra for watering during this establishment phase is  "light and frequent" watering.  Soaking will do more harm than good.  Here's a good document that describes how newly planted trees should be watered.   https://cmg.extension.colostate.edu/Gardennotes/635.pdf  With regards to pruning out interior limbs, I would not recommend it unless the branches are dead, that brittle.  There's no need to expose the tree to unwanted pests during this time of its life.    I hope this helps. Let me know if you have further questions.

responder: The Question Asker Replied August 16, 2024, 9:30 PM EDT
response: Thanks so much for your response and all of these materials, it's much appreciated. We were mistaken on how much water a pinyon would need at this point in time, we'll go back to watering it once a week like we did after it was transplanted. I poked my head inside to check for sap on the branches, and did find a few spots. Attached are the pictures of those spots - do you think anything is attacking or otherwise bothering the tree? Thanks again for your help.

responder: Jeff C, Master Gardener Volunteer Replied August 17, 2024, 2:18 PM EDT
response: Hello again,   Thanks for the photos.   In picture #1, I don't see anything problematic.  Bark will crack and break while the tree is growing.   Picture #2:  That's a fair amount of sap in one area.  Poke around the sap to see if there are any insect larvae.  It could be pinon pitch mass borer.  (see fact sheet below)  The fact sheet also explains how to treat it.   Picture #3: That's a pretty substantial wound. Not sure what it is, but it could be a canker.  How do the needles look beyond that wound?  I would suggest pruning out that branch.  Sterilize your pruner with alcohol or bleach. Then cut out the branch down to where the next joint is.  No need to put anything on the cut.  The tree will heal itself.    Here's the fact sheet on Pinon diseases and insects.  Keep an eye on the tree.  It's a bit stressed out which makes it more susceptible to pests.  https://extension.colostate.edu/topic-areas/yard-garden/pinyon-pine-diseases-and-insects-2-948/  Finally, be sure to water the tree during the fall and winter if it is abnormally dry.  The tree will need about an inch of water every month.  Try to monitor the snow fall to figure out if the melted snow is equal to an inch.  If not, supplemental watering is recommended.  Here's the fact sheet on Fall and Winter watering.  https://extension.colostate.edu/topic-areas/yard-garden/fall-and-winter-watering-7-211/    Let me know if you have any more questions.