if you have a tree how does it reproduce and make seeds that grow into new
trees? do you need two of the same type of tree?

Oh, dear, that is the subject of many books. I'll try to be brief. In most
cases the flowers are pollinated by bees or other insects. The pollinated
flowers turn into fruits which contain seeds. Most conifers are wind
pollinated. The pollen is blown from the male cones to the female cones. The
female cones ripen & contain seeds. Some conifers, like Junipers, have male &
female cones on separate trees, so you need one of each to get seeds. Pine
trees have male & female cones on the same tree. I am not sure about spruces.
In the case of most fruit trees, like apples, although the flowers on all the
trees have both male & female parts, you need two, & sometimes three different
varieties to get fruit.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)