Christmas tree cultivation and oxygen. Nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, boron, copper, chlorine, manganese, molybdenum, iron, and zinc are obtained from the soil. If the necessary elements are not available in the local soil, nutritious fertilizers are used. Other important soil considerations include pH and drainage. Certain types of soil are preferable, depending on the type of tree. Pine trees are usually better adapted to a sandy or sandy loam soil, while white spruce trees and fir trees, such as the Douglas-fir, prefer fine-texture loams and clay loam soils. Some trees grow well in all types of soil, but in any case,
Noble metal Noble metal In chemistry, the noble metals are metals that are resistant to corrosion and oxidation in moist air (unlike most base metals). The short list of chemically noble metals (those elements upon which almost all chemists agree) comprises ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), osmium (Os), iridium (Ir), platinum (Pt), and gold (Au). More inclusive lists include one or more of mercury (Hg), rhenium (Re) and copper (Cu) as noble metals. On the other hand, titanium (Ti), niobium (Nb), and tantalum (Ta) are not included as noble metals although they are very resistant to corrosion. While the