Which trees have resin and why?

Basically, it's about the wound healing of the trees. Since conifers grow slowly, they cannot close wounds fast enough. That's why they have the wonder drug resin at their disposal. Faster growing deciduous trees, on the other hand, form a scar called callus. This always develops where the tree is injured and has the task of covering the wound. Just like the resin in conifers, the callus also closes the wound, preventing the underlying tissue or wood from rotting.

Resin is important for the entire coniferous tree. This is because resin is a substance in the needles that spoils the appetite of predators. If, for example, a louse inserts its proboscis into the needle, the tree reacts. The liquid from the resin cells runs into the puncture wound and closes the hole. The louse often loses its desire or, if it is unlucky, sticks to it. The conifer tree reacts similarly to invaders in the bark, such as beetles. Once these bore into the tree, resin clogs the passageway and prevents them from advancing. Beetles often also remain trapped by the resin as they retreat.

Did you know that amber is fossilized tree resin? The golden-yellow stone develops under many sediment layers and is older than one million years. The special thing about amber is hidden inside. Insects that stuck to the tree's resin ages ago can be found in the fossilized resin chunks: spiders, ants and flies, but also ferns, barks, leaves and needles. They can all be seen tightly sealed in transparent amber. No wonder, then, amber is used for jewelry too.