Plants have two different types of 'transport' tissue. Xylem transports water and solutes from the roots to the leaves, phloem transports food from the leaves to the rest of the plant.
Wooden retaining walls start at around $20 per square foot including materials and installation if using cost-effective pressure treated lumber. Hardwoods such as redwood, Cyprus or mahogany will raise the price over $30 per surface square foot but add an element of beauty to your wall. Railroad ties are the most commonly used wood for a retaining wall, and prices for this type of wall cost between $25 and $30 per square foot of wall. Untreated or soft woods are not recommended for retaining wall construction due to their susceptibility to rot and water damage.
Concrete retaining wall prices start around $30 per square foot including materials and installation and can go as high as $45 to $50 per square foot depending on how much prep work is involved in building the forms. Walls higher than four feet typically require a different type of form which will raise the cost.ood Retaining Wall Prices. Wooden retaining walls start at around $20 per square foot including materials and installation if using cost-effective pressure treated lumber. Hardwoods such as redwood, Cyprus or mahogany will raise the price over $30 per surface square foot but add an element of beauty to your wall.