Let's start with probably the most famous creatures of the Forest; Timberwolves. But to understand them completely, we first need to look at the source of their beloved food.

Zap apple trees

A species well-known thanks to the Apple family's famous jam and the strange phenomena surrounding it. However, such is not the case with the wild specimens. But I am getting ahead of myself there.

I bet that everypony from Hoofington to Appleloosa at least once tasted the jam and heard the story of how did these apples get out of the Forest and into the light of Celestia's sun: the story of a brave filly forced by hunger into the Everfree.

She luckily stumbled upon a clearing with many trees, their branches just bearing the colorful fruit. Really lucky given the Zap apples are ripe only once a year, wasn't she?

That indeed appears as a huge coincidence. And the answer to that is simple; it was not a coincidence. The Zap apple trees in the Everfree bear fruit much more often. It is mainly due to the conditions of the Forest being more favourable to them.

The trees also grow very slowly when present in a grove of their kin, the saplings most likely fed by the older trees via their roots or mushroom hyphae connecting them. When old enough to give fruit, they do so approximately about twice or trice a month. Seeds colonising new land will grow much faster--resulting in the gaunt appearance of these trees and their disability to bear fruit more often--and also call on their innate magic to bring forth the needed weather, if grown outside the Everfree.

Trees grown in the Forest hardly do this, my theory being that the so called "Signs of the Coming Harvest" help the trees in the new environment, with the crows as possible pollinators and meteor showers to scare off herbivors. Or, given they are distant relatives of the Poison Joke, it might be just pure shenanigans without yet known purpose.

Their most typical sites are drier, a little shadowy clearings where the trees usually create groves in the number of three to ten individuals.

Timberwolves
Hierarchy

Unlike normal wolves, Timberwolves lack strict hierarchy and are usually present in family groups or packs of three to eight members, that usually share together one or rarely more of Zap apple tree clearings. The pack is usually led by one individual, usually the eldest. Females with pups might wander further away from the group, but are still treated as members.

You may also encounter Loners, Timberwolves repelled from their packs due to lack of Zap apples or for aggressivity, just wandering around and looking for something edible, individually or uncommonly in smaller groups. These are the ones with the terrible stench coming from their maws, why is it so will be explained shortly.

Diet

Timberwolves feed primarily on Zap apples. They are after them like Princess Celestia after cake Equestian dragons after gemstones and their pack's Zap-tree clearing is the most precious to them.

When there is an overall lack of Zap apples--usually after the sudden return of tough winter and Zap apple buds freezing--the next option are berries, roots and meat. Repelled Loners usually feed on this if they haven't managed to steal a few Zap apples for themselves.

Sadly, there isn't usually enough to sate all Loners, and so some go devouring rotten wood, which is the worst possible option for they metabolism. The wood continues breaking down in their stomach, decomposing the Timberwolves a little on the inside too. This is the source of their stinking breath. So, stinking breath means a hungry and possibly dangerous Timberwolf.

Range

Territories around Zap-tree clearings. They are avoiding the areas where the Cragadiles usually lurk, including Froggy Bottom Bogg and the rocky areas above it.

Reproduction

They are gonochorists, or at least two different mating types are needed for the reproductive process to start. The only reproduction I was able to observe resembled some sort of ritual occuring usually during spring and early summer.

Both partners gather sticks, leaves, bark et cetera from their surroundings or more rarely parts of their own bodies and build the pup from inside to out. The male often iniciates this, presenting a pile of the aforementioned materials it gathered to the female. When the assembling phase is done, both parents freeze in a "howling" position and release part of their magic.

The two magics look a little bit different in appearence and "behaviour", and I've noticed that the same individual always uses the same kind, thus their gender seems to be firmly set. These magics combine and together soak to the body of the little one and it slowly awakes. It stays within the pack, following one of its parents, the mother. The pup is about one third of the size of an adult Timberwolf: height of average pony filly, though longer than that from muzzle to tail. When growing, they attach new pieces of wood into their bodies.

Adults can migrate between nearby packs if there are less members and bigger chance of having more Zap apples for themselves.

Age: Data deficient (not immortal)

Appropriate behaviour

First option: Even the hungry Loners will let you go if you offer them a batch of Zap apples. Throwing a few before their muzzle is enough. But beware taking the apples from the trees on the clearings! As I know, all of them are taken currently.

Second option is carrying around something that you can make "clapping" noises with. The Timberwolves are unable to distinguish it from the clapping of Cragadile jaws. Since those are the only creatures that can seriously hurt the Timberwolves, along with Hydras, they'll wander off. Though it's quite impractical to carry around some pans or pots to make the noise. Also, this doesn't work everytime.

Fire might also seem as a viable option, since these creatures are mostly made of wood. It is not. Someone already tried it on a few. I was lucky (?) enough to be around and witness the consequences. They burn quite slowly and become more aggressive. And as they run around, trying to extinguish themselves, they can set the forest around on fire. So you might escape a Timberwolf, but end up in an inferno of your own... Think about it.

Otherwise I wasn't able to tame them--and I don't want to--but they at least accepted me. Though it took quite a long while and careful maneuvering. They wouldn't attack a pony on the first sight, if not hungry, but don't provoke them.