Ever since the last Ice Age (some 10,000 years ago), this land was covered by forest. Nevertheless it cannot be considered to be a primeval forest (”oerbos”) because the influence of humans has been too important.

Fragments of silex stones, thought to be 3,500 years old, were found. There has been some agricultural activity in certain parts and even remnants of two Roman villas were discovered. Small scale quarrying of sand, stones and iron ore left deep slopes in the landscape.

From the 14^thcentury until the first Wold War the forest was property of the local aristocracy. In 1919 (in the aftermath of Wold War I) the land was confiscated by the Belgian government to be part of the public domain.

The forest houses some plants and animals that are hard to find in other places s.a. the Wild apple (Malus sylvestris). Also the stag-beetle (Lucanus cervus) and fire salamander (Salamandra salamandra) are important species here. 

With its very old oaks, especially the most southern part of Meerdaalwoud is not only the oldest but also the most vulnerable part of the complex.

In 2018, for the first time since 1865, there was a case of breeding of the Raven (Corvus corax). As a couple of Raven stays together for the rest of their life, this looks promising for the future.

Ninety hectares of the forest belong to the ministry of defence and is military area. Until 1976 the area was used to detonate old or obsolete ammunition in a controlled way. In this way, a lot of small pits and embankments were created wherein a variety of fauna and flora could develop. In 2018 the ‘Dijleland study group’ made up an extensive inventory of the birds, mammals and invertebrates on the military domain. And quite a lot of precious and very precious species were spotted.

In 2005, ANB built the Ecoduct “De Warande” the first one to be constructed in Flanders. The ecoduct connects the eastern and western parts of the forest complex across a busy north-south road that splits the forest in half. It offers a safe way for animals to pass from one side of the forest to the other without the risk of being killed by the traffic. Up to now more than 200 different species were identified to use the ecoduct. Not only mammals such as deer, wild boar, marten, weasel, fox, squirrel, badger but also 7 species of bats, 51 species of beetles, some of them threatened, and 100 spider species, 17 among them on the red list. Not only fauna but also flora is important: a lot of forestplants are already covering the ecoduct.

This year the construction of a second ecoduct was started.

The Meerdaalwoud complex is situated at a mere 15 km from another, even vaster forest, the Zoniënwoud. The latter is spreading out over the Flemish, Brussels and Walloon regions. In between there are the valley of the river Dijle, the beautiful grassland “De Doode Bemde” (see the BioAct by Greet Sienap), an old slope forest (Roodebos) and some large pools.

Some visionaries are already dreaming now to bring together these various elements into one large, beautiful and divers National Park.

https://www.naturalsciences.be/en/science/home

The red fox (Vulpes vulpes) is the largest of the true foxes.

Red foxes are omnivores with a highly varied diet. They primarily feed on small rodents like voles,mice, ground squirrels hamsters...Secondary prey species include birds, reptiles, insects, other invertebrates.They typically target mammals up to about 3.5 kg in weight, and they require 500 grams of food daily. Red foxes readily eat plant material, and in some areas fruit can amount to 100% of their diet in autumn.

Red foxes prefer to hunt in the early morning hours before sunrise and late evening.Although they typically forage alone, they may aggregate in resource-rich environments.When hunting mouse-like prey, they first pinpoint their prey's location by sound, then leap, sailing high above their quarry, steering in mid-air with their tails, before landing on target up to 5 metres away.

A nice film of “a fox catching a mouse in the snow” you can find on:http://www.arkive.org/red-fox/vulpes-vulpes/video-08b.html

A mouse is a small rodent characteristically having a pointed snout, small rounded ears, a body-length scaly tail and a high breeding rate.

Cats, wild dogs, foxes, birds of prey snakes and even certain kinds of arthropods have been known to prey heavily upon mice. Nevertheless, because of its remarkable adaptability to almost any environment, the mouse is one of the most successful mammalian genera living on earth today.

Primarily noctural animals, mice compensate for their poor eyesight with a keen sense of hearing, and rely especially on their sense of smell to locate food and avoid predators.

The Eurasian nuthatch or wood nuthatch (Sitta europaea) is a small passerine bird found throughout temperate Asia and in Europe. It is a short-tailed bird with a long bill, blue-grey upperparts and a black eye-stripe.
The preferred habitat is mixed woodland with large, old trees, preferably oak.

The Eurasian nuthatch eats mainly insects, particularly caterpillars and beetles, although in autumn and winter its diet is supplemented with nuts and seeds.
The nuthatch can forage when descending trees head first, as well as when climbing.

(Its main natural predator is the Eurasian sparrowhawk.)

Caterpillars are thee larval stage of members of the order Lepidoptera
Caterpillars of most species are herbivorous, but not all
Caterpillars are typically voracious feeders and many of them are among the most serious of agricultural pests. Conversely, various species of caterpillar are valued as sources of silk, as human or animal food, or for biological control of pest plants.
Caterpillars have soft bodies that can grow rapidly between moults.
Many animals feed on caterpillars as they are rich in protein. As a result, caterpillars have evolved various means of defense.

Ixodes ricinus, the castor bean tick, is a chiefly European species of hard-bodied tick. It may reach a length of 11 mm when engorged with a blood meal, and can transmit both bacterial and viral pathogens such as the causative agents of Lyme disease and tick-borne encephalitis.

Ixodes ricinus has a three-host lifecycle, which usually takes 2–3 years to complete. Adults feed on large mammals such as sheep, cattle, dogs, deer, humans, and horses for 6–13 days, before dropping off. An engorged female lays several thousand eggs and subsequently dies. The larvae that hatch do not actively seek a host, and usually feed on insectivores. They feed for 3–5 days before dropping off and moulting. The resulting nymphs then ascend grasses or twigs to seek their next host.  The nymphs feed on small to medium-sizedmammals.

The female Stylops melittae gives birth to a large number of motile primary larvae, that are strewn upon blossoms. From there they can be delivered along with the pollen at the nest construction of the sand bees for which the species is specialized. 
In the nest construction the primary larvae penetrate into the host larvae and molt into exclusively endoparasitic secondary larvae. These roam about feeding in the host, and after a few further moltings establish themselves in the abdomen, and with their anterior portion break through between two abdominal segments of the host's skin, where they pupate.

Females spend most of their lives in the tree canopy, favouring dense and mature oak woodlands, coming down only to lay their eggs in the small sallow bushes that grow in clearings and rides.

Males also spend much of their time in the tops of a big striking tree, defending their territory from rivals.

Though they will sometimes descend to drink from puddles or feed. Unlike most butterflies, the purple emperor does not feed from flowers but instead on the honeydew secreted by aphids, sap oozing from oak trees, and on dung, urine and animal carcasses.

They lay eggs in late summer on the upperside of sallow leaves, preferring the broad-leaved sallow, Salix caprea.

After hatching, the larvae will lie along the midrib of the leaf where they are well camouflaged, and feed only at night. 

During the winter they hibernate in the forks of sallow branches, where they change colour from green to brown to match their surroundings. 

The following June they form a pale green chrysalis resembling a leaf shoot. 

The adults usually emerge in July, flying well into August.

Slowworms are semifossorial (burrowing) lizards, spending much of the time hiding underneath objects. The skin of slowworms is smooth with scales that do not overlap one another. Like many other lizards, slowworms autotomize, meaning that they have the ability to shed their tails to escape predators.

They are carnivorous and, they feed on slugs and worms

The females give birth to live young (ovoviviparous birth).

Adult slowworms grow to be about 50 cm long, and are known for their exceptionally long lives; the slowworm may be the longest-living lizard, living about 30 years in the wild.

The slow worms are often found in ant heaps, which are used as hiding places. Especially the young Anguidae spend a large part of their time in ants heaps. They have nothing to fear from the ants through the armored skin and the small eyes. Moreover, they benefit from the fierce protection of the nest against joint enemies such as the Shrew.

Leisler's bat (Nyctalus leisleri): EN

Pond bat (Myotis dasycneme): EN

European polecat (Mustela putorius): VU

European pine marten (Martes martes): CR

European badger (Meles meles): VU

Garden dormouse (Eliomys quercinus): EN

Hazel dormouse (Muscardinus avellanarius): CR

Prunus serotina was widely introduced into Western and Central Europe as an ornamental tree in the mid 20th century, where it has become locally naturalized. 
It has acted and still act as an invasive species, negatively affecting forest community biodiversity and regeneration. 

Foresters call it the plague of the forest. Also in Meerdaalwoud it became a big problem.

Extreme weather conditions such as drought and heat waves can cause forest fires, storms can cause uprooting by wind. But slower changes can also lead to mutations in different tree species.

Prolonged droughts in the summer cause water stress in forests. This stress can have different effects depending on the species. Trees weaken both by prolonged water stress and during short heat periods. They are more susceptible to attacks by xylofage (wood-eating) insects. Moreover, the species of trees currently living in our forests are not adapted to the drier climate that Belgium is expected to face in the coming decades. This is especially the case for the Norway spruce (a species that descends from the mountains) but also for the beech which is equally susceptible to drought. The beech is a very important species in Meerdaalwoud.