Lyophyllum is a big genus that encompasses a lot of different mushrooms. Lyophyllum Decastes does not generally grow on trees so I would suggest these are not Lyophyllum Decastes. At any rate, Lyophyllum Decastes are not a beginner mushroom. I would not recommend eating something that you think is Lyophyllum Decastes without getting an identification from someone in person who is experienced in picking this variety. There are several poisonous and Tricholoma species that are very hard to differentiate from Lyophyllum Decastes.