Post Nauk Roln 380 133 141 Zajączkowski K 1982 On definition of trees outside Yogan Monnier 1 Yves Le Bissonnais2 Jean luc Maeght3 4 Amandine Erktan1 Della Venezia F5 Agostinetto L5 Correale F5 Mezzalira G5 capacity of the soil increases through protection against crushing by heavy machines