I am not an expert on Yamadori so I will let the experts do the talking... read the below articles:
http://www.bonsai4me.com/AdvTech/ATcollectring%20trees%20from%20the%20wild%20W%20Pall.htm
http://ofbonsai.org/techniques/collecting/yamadori-2
http://ofbonsai.org/techniques/collecting/collecting-yamadori-in-southeastern-europe
http://ofbonsai.org/galleries/insperation/yamadori-along-the-adriatic-coast
http://ofbonsai.org/species-specific/tropical/pemphis-acidula-%e2%80%93-pearls-in-the-tropics
- AH