age circles log nature old oldness rings science tree wood annual rings firewood lines live time lumber jack material old age raw material substance texture tree trunk trunk wood texture woodgrain axe background bark circle concentric count cut end felled forest forestry pile ring saw timber wooden age-rings angles block brown chopping colored coloring colors coloured colouring colours crack cracked cracks cuts drying exposed grooved grooves length lengths logs lopped orange perspectives rough sawn surface surfaces textures tree-block tree-rings uneven blocks pieces piled tree-blocks woodpile