Dantzic timber is any timber that was exported from the Baltic port of Danzig, now known as Gdansk.
Gdansk is on the mouth of the Motlawa river and thus had good water access to the large inland areas of N.E. Europe.
Timber species exported included softwood from various Spruces, Pines and Firs. Hardwoods included Oak, Beech and Ash.
"Pitch Pine" is a generic term for some of the Tropical/ sub-Tropical Pine species such as P. caribaea which have a very high resin content and thus are thought more resistant to moisture decay and insects. I am not aware that this trade occurred in Gdansk.
Danzig timber became very important to Great Britain after about 1575 when sources of home grown timber became more scarce. Hobhouse comments that the last ship load of structural timber to be exported from Britain was in 1588. He and others attribute this shortage of timber (both for structures and fuel) as one of the main incentives to adopt and seek coal, as well as importing timber from N.E.Europe.
See:- Hobhouse. Seeds of Wealth. ISBN 0 330 48812 0