Scott, here are eight men's American voices reading both of your scripts, word for word. The deepest voices come first. All of them come from free voice software running on my own computer. If none of them suits, I can make samples from ElevenLabs next.
Timing: read at a natural pace, the 30-second script takes 65–81 seconds and the 45-second script 92–118 seconds. Both have roughly twice as many words as fit (158 and 237 words; 30 seconds holds about 75 words, 45 seconds about 110).
Once you've picked a voice, I can suggest trimmed versions of the scripts for you to edit, and then time the narration to the vertical cut of the video.
Listen for which voice you like, not the pace; the pace can be adjusted. Reply with the letters you like.
Draft: your video with voice G reading the 45-second script
1 min 53 s. To show how a narrated version could feel, I re-cut your footage to the narration rather than squeezing the narration into 50 seconds. Each paragraph plays over the footage that matches it: the opening over the palm landscapes, the history over Bulletin No. 1, the journal and books over the covers, conservation over the forest, the meetings over the garden tour, International Palm Day over the sealing-wax palms, and the web address over the end card. Clips are slowed to fit, which is why some motion looks soft. With a trimmed script, the footage could run near normal speed. Landscape for now; the vertical version comes next.
The voices
A · deep
Supertonic 3, voice M5 · speaking pitch about 90 Hz
B · deep
Kokoro, voice Onyx · speaking pitch about 87 Hz
C · deep, younger
OmniVoice, made from the description "male, young adult, low pitch, American accent" · about 88 Hz
D · deep
Supertonic 3, voice M2 · about 92 Hz
E · baritone, quicker
Supertonic 3, voice M3 · about 100 Hz
F · baritone, younger
OmniVoice, made from the description "male, young adult, very low pitch, American accent" · about 105 Hz