autumn change fieldnature oak oak tree seasons tree clouds nature season summer spring acorns fall fall acorns squirrel bare branches crown dead death end mortality Quercus flower flowers green midsummer oak-tree trees yellow bark branch crevice forest hardwood jungle mata plant root Roots texture tronco tropical vegetation verdura wood background cork oak crack crevasse rough rugged blue sky farmland field foliage grass leafs meadow noon october sunny sunshine colour leaves sky landscape old rural