green lichens on a trunk in a chestnut wood

air algae autumn background bark biology botanical botany castanea chestnut closeup color colors colour coming crustose cut cyanobacteria detail during ecosystem environment fagaceae fallen filaments flora foliage foliose forest fungi fungus green growing growth italian leaves lichen lichens macro miller moss natural nature outdoor pattern plant purity relationship sativa seasons squamulose surface symbiosis symbiotic texture tree trunk wild winter wood yellow