The Mata Nacional do Buçaco is located 550 meters above sea level at the highest point of the Serra do Buçaco mountain range. The forest area is surrounded by a high, 5-kilometre-long wall. Actually, it is an arboretum with a multitude of endemic trees and shrubs and exotic species brought by the Portuguese seafarers from the colonies.

Coming from Coimbra I arrived in the forest in the morning and in the thick fog, which often seems to occur in Buçaco. I entered the forest through one of the eleven gates and paid 5 euros for parking, the entrance is free for pedestrians and cyclists (you can also park the car outside the walls).
In the centre of the park is the neo-Manueline Buçaco Palace, built for the last Portuguese king. Today the palace is a 5-star hotel, I could only take a short look into the entrance hall and the restaurant, looks nobel and luxurious. From the outside it has similarities with the Quinta da Regaleira Palace in Sintra.
Right next to the Palace is the former Convento de Santa Cruz do Buçaco, or rather its remains. Large parts were destroyed for the construction of the Buçaco Palace or are today integrated into the hotel complex. The chapel of the convent has been preserved, but unfortunately it was closed for renovations. The façade is decorated with black-white mosaics and looks quite nice.
There are a number of hiking trails starting at the palace, I chose the Via Sacra up to the highest point in the forest, the Cruz Alta. Unfortunately, many of the small chapels and ermidas along the trail are in poor state of preservation. The photo shows one of the larger and better preserved buildings. The area between Cruz Alta and the Porta de Coimbra, called Adernal, is supposed to be the most picturesque part of Buçaco. The fog was still dense, that gave my hike a bit of a spooky atmosphere.
The Buçaco Park is a dense wood, more like a primeval forest than a landscape garden, there are not many buildings apart from the palace and the chapels along Via Sacra. Worth mentioning is the Fonte Fria, where you can follow the water over 140 steps downhill to an artificial pond.

If the Buçaco Forest were in the Sintra mountains, it would be just one among many parks, and not the most popular I guess. Manueline architecture, monasteries and parks are already well represented on the Portuguese WH list and by better examples. The biodiversity of trees and shrubs in Buçaco could be of outstanding value, I'm not an expert in this field, but I doubt that this would justify an inscription. Maybe my assessment would be less negative if I had visited the forest in better weather and if I could have enjoyed the viewpoints, but in my opinion this tentative site does not provide additional value to the World Heritage list.