#tree {
    position: absolute;
    width: 50%;
    height: auto;
}

#tree2 {
    position: absolute;
    width: 50%;
    height: auto;
    left: 0px;
}

.nature {
    z-index: -1;
    position: absolute;
    opacity: 0;
}

.lake_nature {
    z-index: -1;
    position: absolute;
}