A fairly recent trend in pruning in Las Vegas has been pruning pine trees so they don’t blow over. We have some wind gusts that periodically get pretty nasty when they reach speeds of up around 70 mph (112 kph) or more. The trend was to remove some of the canopy so that there is not so much leverage on the root systems. This leverage, or sail effect, by the wind can pop the trees over when gusts come up quickly and our trees can be pretty shallow rooted which does not help to anchor them. This Mondale pine was pruned probably  in an attempt o reduce with wind load (sail effect)  on its canopyand help reduce the potential for blowing over You can see that removing the inner small branches concentrates the weight of the new growth all on the ends of the branches causing  them to bend and in some cases to break   I have some concerns about thinning pine trees to allow more wind to blow through their canopies. Not that it is done but really more about HOW it is done. Take a look at this picture of a pruned pine tree just for that purpose. Most pine trees will not regenerate new growth on older branches once this growth is removed. Once the wood is older than about three years old most pines will not cause new growth to come from this older wood. Once this young wood is totally removed, it is gone for good. By removing these small limbs in the interior it prevents pines like Mondale from renewing the removed growth. The juvenile part of the limb is now concentrated only in the growing tips which are all at the ends of the branches. This might be good in theory (the tree trimmers don’t have to come back as often). But this can create a problem.Think of a fishing pole. Why is the pole diameter tapered and not all the same diameter along its length? Poles or branches which are tapered help spread the stresses of bending along its length. If a pole or branch has no taper, then the stress of bending is concentrated in a very small area of the pole or branch which will increase its chances of snapping or breaking. By removing this small wood deep on the inside it also causes these “thinned” older limbs to no longer increase in girth (caliper or diameter).They bend more and more as the weight of the new growth is added to the ends of the branches. Pine tree with a canopy thinned a bit better so that limbs are less likely to bend and split A better approach would be to selectively leave some juvenile wood on the interior of these larger diameter branches so that these branches will increase in caliper and taper. So instead of removing ALL the small juvenile from branches deep in the inside, remove some but leave some as well. This still results in thinning and allows for wind to move throught the canopy easier and also results in distributing this increased load along the branches rather than concentrating the load in a small area of the branch which increases its likelihood of failure (snapping or bending). Just a thought.