All summer we say the trees are storing energy getting ready for winter. 

I am curious about this; what is the form of energy and where it is. Does cutting a  branch off remove energy, so pruning is better in the spring after all energy is used up?

I know where I store energy. I don’t see a similar bulge on the trees.

LOL, I got that bulge too 🤣🤣.

First of all trees store non moveable energy in the wood. That is why we use it sometimes to heat our house. I use birch. 1m3 contains 2660 kWh of energy.

The amount of energy the trees store in winter to help flush spring growth is not at all comparable to our belly fat or the wood. It is comparable tiny amounts and is stored as sugar and starches in the sap, which flows between the roots, sapwood and leafs. While not much energy in the sap, it can be tremendous amounts of it. A big birch can be tapped on 15 liters of sap in one springday without damaging it. The total flow is several times higher and goes on for weeks in spring. Traditionally we have used it for drinking. It was an important source of energy in the part of the year when food storage was on low levels and the hard work of spring plowing, and sowing started.

Conifers on the other hand have resin. That is a substance that has much more energy per volume. It is thick and sticky and flow much slower. It is easy to understand just by looking at the growth pattern. A birsh sprouts tremendous amounts of leafs in a very short time in early spring. Leavs with a huge surface area that transpires a lot of water when sun gets strong. They need relativelly more water than energy and it needs to flow fast. Pines on the other hand, having evergreen needles do not transpire that much. The resin flows slover and the flush of growth is later.

The resin is traditionally used to extract tar, which is very high in energy.

Pibe resin also is used to make turpentine, which really burns hit.

And, of course, there is the gift our Canadian friends have given the world, maple sugar.

I guess thus means I could trim small twigs after the leaves fall, but should avoid larger surgery until spring.