No timber = no ships, no ships = no Dutch: an anti-Dutch plan
Timber was an indispensable material until the period known as the industrial revolution was consolidated. Timber was the first construction material available to the human species. The forest was the main source of supply for human activities: It was a wooden source for utensils, tools, weapons, furniture, buildings, and ships; food source for animals and even for people; fuel source for kitchens, foundries and fertilizer for agricultural work. All the components of the tree were usable: the trunk and branches as fuel or raw material for manufacturing and construction, the leaves as fertilizer or animal and human food, the bark for the manufacture of dyes and shoes. Despite the fact that during the early modern era, these uses were maintained, the new circumstances made some of them become more important in comparison with others. From the 16th to the 18th century, timber continued to be an essential raw material, used in all kinds of domestic, industrial and, above all, military tools.
General Archive of Simancas (AGS), EST
The document that I present you next, can help us to get an idea of how important timber was. So important that it could cause a state to collapse. Or at least that was the opinion of Pedro Bolders, a German captain (raised in Norway) who has already been in the service of Philip II for eighteen years. He proposed to the king in 1597 a plan "for the destruction of his enemies". The enemies referred were the Dutch rebels and what he proposed was to block their timber trade, preventing them from maintaining and expanding their navy, the foundation of their power:
It is notorious to all of us that Holland and Zealand build four hundred and more ships every year without having any timber there except for the one that comes from outside. And thus taking away the timber for a few years, would be to take away the main livelihood of the Republic, since it has no other income than from the dominance of the sea and the fishery. And to snatch this from them, the following could be done.
Your Majesty can command by secret intelligences to deal with the King of Denmark and his ministers who rule in his Kingdom of Norway, that his vassals do not cut or sell for some years any oak tree, since it comes from Norway all the timber used in Holland and Zealand. And although through the Rhine river and the province of Gelderland could arrive some [timber], it will be easy to take it from them, because Your Majesty has various fortresses on the mentioned Rhine river and in the province of Gelderland.
As far as I know, this plan was never carried out. Although relations with the Protestant Denmark were not bad, they were not so good as to make them give up such a lucrative trade and oppose their neighbours xD
 Aragón Ruano, Á. (2001) El bosque guipuzcoano en la Edad Moderna: aprovechamiento, ordenamiento legal y conflictividad. Aranzadi Zientzi Elkartea, Donostia-San Sebastián, 2001, p. 63.
Aguilera López, A. J. (2020) "No timber = no ships, no ships = no Dutch: an anti-Dutch plan", in Rowing through History [online].