Units used are in metres. The characters tend to be a little taller than is accurate.
Mass is in kilograms. Most of the people who have defined these things are European, and I guess it shows a little.
Burn speed is a slighly abstract concept. I don't remember off the top of my head how to translate it into something comprehensible.
Fruit chance is a number used to calculate whether a fruit grows on a tree in a given 30 second tick. The higher the number, the lower the probability. I admit this does not make sense. The probability is 1 divided by fruitChance that a fruit will grow in a given tick.